I dissent. The majority hold that a defendant in custody facing two unrelated charges is entitled to pretrial custody credit against the first sentence imposed, but he is not entitled to such credit when sentence is imposed for the second charge, “unless it is demonstrated that the claimant would have been at liberty during the period were it not for a restraint relating to the proceedings resulting in the later sentence.” (Maj. opn. at p.489.) However, the applicable statute and established case law demonstrate that a defendant facing two unrelated charges is entitled to pretrial custody credit on each charge until he starts serving a term of imprisonment on one of them. The rule established by the majority for the awarding of pretrial custody credit is inequitable; it discriminates against indigent defendants. It is inconsistent with our previous interpretation of the applicable statute, and it will prove to be an administrative nightmare.
Penal Code section 2900.5 provides in pertinent part: “(a) In all felony and misdemeanor convictions, either by plea or by verdict, when the defendant has been in custody, including . . . any time spent in a jail, . . . prison, ... or similar residential institution, all days of custody of the defendant, . . . shall be credited upon his term of imprisonment. . . . [fl] (b) For the purposes of this section, credit shall be given only where the custody to be credited is attributable to proceedings related to the same conduct for which the defendant has been convicted. Credit shall be given only once for a single period of custody attributable to multiple offenses for which a consecutive sentence is imposed.”
We have established that a defendant’s entitlement to custody credit for multiple restraints ends when the defendant begins serving a term of imprisonment. (In re Rojas (1979) 23 Cal.3d 152, 156 [151 Cal.Rptr. 649, 588 P.2d 789].) The defendant is nonetheless entitled to dual credit for multiple restraints before he begins serving a term; the defendant need only show that the charge as to which he seeks credit was a basis, not necessarily the exclusive basis, for the custody. (In re Atiles (1983) 33 Cal.3d 805, 810 [191 Cal.Rptr. 452, 662 P.2d 910].)
In In re Rojas we explained that the purpose of section 2900.5 is to “eliminate the unequal treatment suffered by indigent defendants who, because of their inability to post bail, served a longer overall confinement than their wealthier counterparts. [Citations.]” (In re Rojas, supra, 23 Cal.3d 152, 156, and cases cited.) Thus without section 2900.5, an indigent who is *497unable to post bail and waits for trial for six months, would serve six months longer than the prisoner who is convicted of the same offense, but was able to avoid pretrial confinement by posting bail. When a defendant is serving a term of imprisonment, however, and is accused of a second unrelated offense, it is not his indigency which causes him to be unable to gain his freedom pending trial. A prisoner may be rich as Croesus, but he will remain in prison along with his indigent cellmate, while new charges are tried against each of them. Thus we rejected the claim of a man serving a prison term for manslaughter for credit against a subsequent term for murder. The murder charge was filed after the defendant started serving his term for manslaughter; it had no conceivable effect on his custody. His custody was not attributable to the second offense. (23 Cal.3d at p. 156.)
Similarly, in In re Atiles we explained at length that unequal treatment of indigents may follow from denial of credit on multiple concurrent terms. (In re Atiles, supra, 33 Cal.3d 805, 812-813.) The accused who has sufficient funds to post bail in two separate proceedings against him, and who is ultimately sentenced to concurrent terms in those proceedings, will serve less time in custody than the indigent who is also sentenced to concurrent terms for identical offenses, but who was unable to post bail in one or both of the proceedings. That is, this unequal treatment will result unless the indigent is able to receive credit for pretrial custody against both of his concurrent terms.
In Atiles we made it clear that dual credit is available when defendant is under multiple restraints, as long as defendant is not serving a term of imprisonment. Atiles was on parole when he was charged with two new offenses. A parole hold was placed on him, and shortly thereafter his parole was revoked and he was returned to prison for six months. After the expiration of the six months, he pleaded guilty to one of the new offenses. We said that he was entitled to credit against the new sentence for the time spent in prison for the parole revocation. We rejected the argument that since the parole revocation custody was attributable in part to the offense which was apparently dropped as part of a plea bargain, the revocation time was not attributable solely to the new offense on which defendant was sentenced. We explicitly rejected the contention that Rojas held that pretrial credit is available only when custody is attributable exclusively to the offense defendant is ultimately sentenced on. Regarding Rojas, we said: “It was not a holding that the custody must be attributable exclusively to the conduct underlying the term ultimately imposed." (Atiles, supra, 33 Cal.3d at p. 810.) In a footnote, we explained the absurd consequence of the Attorney General’s argument: “Were we to accept that proposition, credit would be denied a nonparolee charged with two offenses and acquitted of one." (Id. at p. 810, fn. 4.)
*498To make it absolutely clear that pretrial custody credit should be awarded even if custody was not exclusively attributable to the offense defendant is being sentenced on, we instructed trial courts: “In determining whether custody for which credit is sought under section 2900.5 is ‘attributable to proceedings leading to the conviction,’ the sentencing court is not required to eliminate all other possible bases for the defendant’s presentence incarceration. The court need only determine that the defendant was not already serving a term for an unrelated offense when restraints related to the new charge were imposed on him, and the conduct related to the new charge is a basis for those restraints. [Fn.]” (In re Atiles, supra, 33 Cal.3d at p. 810, italics added.)
Although Atiles involved the combination of a parole revocation and a new conviction, and the offenses all took place in California, its principles dictate the result in this case. In order to warrant credit under section 2900.5, custody need not be exclusively attributable to the offense for which credit is sought, as long as the custody was not served under sentence for another conviction. All of this flows naturally from the intent of the Legislature in enacting section 2900.5 to equalize the position of indigents and nonindigents with respect to pretrial custody credit. Accordingly, since defendant’s custody in Florida and California, up until the time sentence was imposed on him in Florida, was attributable in part to the California charges, he is entitled to credit under section 2900.5 for that period.1
The majority contend that Atiles permits dual credit only where the subject term and the pretrial custody are based on the same criminal conduct. In fact, the parole revocation in Atiles was based in part on an offense of which defendant was never convicted and for which he was never sentenced, so it is not true that there the subject term and the pretrial custody were based entirely on the same conduct. In any event, we made it clear that the rationale of our decision extended beyond cases involving the same criminal conduct. We said that two legislative purposes animated section 2900.5: “‘eliminat[ing] the unequal treatment suffered by indigent defendants who, because of their inability to post bail, served a longer overall confinement than their wealthier counterparts’ [citation] and equalizing the actual time served in custody for given offenses. [Citation.]” (Atiles, supra, 33 Cal.3d at p. 812.) We observed that “[u]nequal treatment follows not *499only from denial of credit altogether for presentence jail time, however, but also from denial of credit on multiple concurrent terms. This may occur if a defendant seeks separate trials on severable charges to ensure his right to a fair trial, if a prosecutor does not join multiple counts in a single accusatory pleading, or if a defendant faces charges in more than one jurisdiction. It may also occur in cases such as this in which parole revocation proceedings and new charges are pending simultaneously if the defendant does not promptly plead guilty and seek immediate sentencing. In each of these situations, the possibility of unequal treatment exists if concurrent terms are imposed, but because sentence has been imposed or parole revoked in the first proceeding before the others are tried, credit for time in jail while awaiting disposition of the remaining charges is denied. The terms then are not truly concurrent since the effect of denying credit on the later terms is that they commence only on the date sentence is pronounced. The time between sentencing in the first proceeding and that in the second is, as to the second term, ‘dead time.’ The Legislature has not either expressly or by implication indicated an intent to deny dual credit in any of these situations.” (Id. at pp. 812-813, italics added.)
The majority repudiate the concern we expressed in Atiles with ensuring concurrency of sentences as unsupported by any legislative history, and as unnecessary to the opinion. But our discussion in Atiles of the twin legislative purposes of section 2900.5 was not mere surplusage. In fact, ensuring concurrency of sentences is simply a necessary corollary of the overriding concern that indigents not serve longer terms simply because of their indigency. An indigent who faces trial on two unrelated charges and receives concurrent terms on these charges should not serve a longer sentence than one who faces the same charges and terms, but was able to post bail.
The majority argue that if Atiles is correct in asserting that section 2900.5 was intended to assure true concurrency of sentences, there is no reason to deny credit for term-serving time. The opinion argues that our conclusion, if followed to its logical end, calls for the overruling of Rojas. (See maj. opn. at pp. 494-495.) Not at all. Our concern with ensuring concurrent sentences should be understood in light of the Legislature’s obvious intent to equalize the position of indigent and nonindigent pretrial detainees. A person serving a term of imprisonment cannot achieve his freedom whether he is rich or poor. Therefore there is no unfairness in holding that the prisoner’s “pretrial” detention is not attributable to the new offense.
The majority would have us expand Rojas and reject Atiles, and take the position that a person is not entitled to pretrial custody credit under section 2900.5 unless he can demonstrate that his custody was solely attributable to the offense for which he seeks credit, and in fact that he would have been at *500liberty but for that restraint. (See maj. opn. at p. 489.) In Rojas, we did say that “Section 2900.5 does not authorize credit where the pending proceeding has no effect whatever upon a defendant’s liberty.” (23 Cal.3d at p. 156.) The context of this statement, however, is that the defendant’s prison term made the wealth-equalizing function of section 2900.5 irrelevant. When two unrelated charges keep the defendant in custody before trial, however, the wealth-equalizing function of section 2900.5 should come into play.
To hold, as the majority do, that a defendant is not entitled to credit unless he can show that his custody was attributable solely to the offense of which he was convicted means that whenever there are dual restraints arising from unrelated charges, the indigent who cannot post bail receives pretrial custody credit only against the first-imposed sentence. The indigent who faces two separate, unrelated charges may for example, be charged with burglary, and bail is set at $10,000. He is charged with a second unrelated burglary, and bail is set at $20,000. He is convicted of both, and is sentenced to concurrent terms. Under the majority rule, only the person who could post bail on both charges can obtain a fully concurrent sentence on the charges. If he cannot post bail on the first charge, he gets credit for pretrial custody against that charge, but not against the second charge, since he cannot establish that his custody was solely attributable to the second charge. Thus the second sentence cannot be made fully concurrent with the first if defendant is indigent, while it can be made fully concurrent if he has money to post bail.
Finally, the interest of judicial efficiency militates against a system requiring minitrials at the sentencing hearing, where the parties sift through the evidence to determine whether there are multiple bases for the defendant’s pretrial custody. A traffic warrant, a technical probation revocation, a warrant on an offense of which defendant was ultimately acquitted, all may have contributed to defendant’s custody. The majority would require defendant to allege that he would have been released in Florida but for the California hold; this allegation puts at issue the bail and own-recognizance-release practice of another jurisdiction. We should not impose on the already burdened trial courts the obligation to determine the inherently speculative question whether, but for the charge on which defendant was convicted, defendant would have been free from custody.
I would order the trial court to modify the judgment to grant petitioner pretrial custody credit for the time that he was in custody in Florida after *501the California hold was placed on him until he began serving the term of imprisonment under the Florida conviction.
Arguelles, J.,* concurred.
Petitioner’s application for a rehearing was denied May 24, 1989. Broussard, J., was of the opinion that the application should be granted.
The majority claim that there is no evidence that the California warrant hold had any effect on defendant’s custody in Florida at any time. (Maj. opn. at p. 490.) I need only note that under the Uniform Agreement on Extradition, of which Florida is a signatory, it is the obligation of the state which discovers a fugitive from criminal charges in another state to arrest the fugitive. (See Pen. Code, § 1548.1.) Subject to certain procedural requirements, the receiving state must then deliver up the fugitive to the demanding state. (Ibid.) This is what Florida did.
Retired Associate Justice of the Supreme Court sitting under assignment by the Chairperson of the Judicial Council.