delivered the opinion of the Court.
We granted the writ in this case to consider petitioner’s claim that a statement made by him to police under circumstances rendering it inadmissible to establish the prosecution’s case in chief under Miranda v. Arizona, 384 U. S. 436 (1966), may not be used to impeach his credibility.
The State of New York charged petitioner in a two-count indictment with twice selling heroin to an under*223cover police officer. At a subsequent jury trial the officer was the State’s chief witness, and he testified as to details of the two sales. A second officer verified collateral details of the sales, and a third offered testimony about the chemical analysis of the heroin.
Petitioner took the stand in his own defense. He admitted knowing the undercover police officer but denied a sale on January 4, 1966. He admitted making a sale of contents of a glassine bag to the officer on January 6 but claimed it was baking powder and part of a scheme to defraud the purchaser.
On cross-examination petitioner was asked seriatim whether he had made specified statements to the police immediately following his arrest on January 7 — statements that partially contradicted petitioner’s direct testimony at trial. In response to the cross-examination, petitioner testified that he could not remember virtually any of the questions or answers recited by the prosecutor. At the request of petitioner’s counsel the written statement from which the prosecutor had read questions and answers in his impeaching process was placed in the record for possible use on appeal; the statement was not shown to the jury.
The trial judge instructed the jury that the statements attributed to petitioner by the prosecution could be considered only in passing on petitioner’s credibility and not as evidence of guilt. In closing summations both counsel argued the substance of the impeaching statements. The jury then found petitioner guilty on the second count of the indictment.1 The New York Court of Appeals affirmed in a per curiam opinion, 25 N. Y. 2d 175, 250 N. E. 2d 349 (1969).
At trial the prosecution made no effort in its case in chief to use the statements allegedly made by petitioner, *224conceding that they were inadmissible under Miranda v. Arizona, 384 U. S. 436 (1966). The transcript of the interrogation used in the impeachment, but not given to the jury, shows that no warning of a right to appointed counsel was given before questions were put to petitioner when he was taken into custody. Petitioner makes no claim that the statements made to the police were coerced or involuntary.
Some comments in the Miranda opinion can indeed be read as indicating a bar to use of an uncounseled statement for any purpose, but discussion of that issue was not at all necessary to the Court’s holding and cannot be regarded as controlling. Miranda barred the prosecution from making its case with statements of an accused made while in custody prior to having or effectively waiving counsel. It does not follow from Miranda that evidence inadmissible against an accused in the prosecution’s case in chief is barred for all purposes, provided of course that the trustworthiness of the evidence satisfies legal standards.
In Walder v. United States, 347 U. S. 62 (1954), the Court permitted physical evidence, inadmissible in the case in chief, to be used for impeachment purposes.
“It is one thing to say that the Government cannot make an affirmative use of evidence unlawfully obtained. It is quite another to say that the defendant can turn the illegal method by which evidence in the Government’s possession was obtained to his own advantage, and provide himself with a shield against contradiction of his untruths. Such an extension of the Weeks doctrine would be a perversion of the Fourth Amendment.
“[T]here is hardly justification for letting the defendant affirmatively resort to perjurious testimony in reliance on the Government’s disability to challenge his credibility.” 347 U. S., at 65.
*225It is true that Walder was impeached as to collateral matters included in his direct examination, whereas petitioner here was impeached as to testimony bearing more directly on the crimes charged. We are not persuaded that there is a difference in principle that warrants a result different from that reached by the Court in Walder. Petitioner's testimony in his own behalf concerning the events of January 7 contrasted sharply with what he told the police shortly after his arrest. The impeachment process here undoubtedly provided valuable aid to the jury in assessing petitioner’s credibility, and the benefits of this process should not be lost, in our view, because of the speculative possibility that impermissible police conduct will be encouraged thereby. Assuming that the exclusionary rule has a deterrent effect on proscribed police conduct, sufficient deterrence flows when the evidence in question is made unavailable to the prosecution in its case in chief.
Every criminal defendant is privileged to testify in his own defense, or to refuse to do so. But that privilege cannot be construed to include the right to commit perjury. See United States v. Knox, 396 U. S. 77 (1969); cf. Dennis v. United States, 384 U. S. 855 (1966). Having voluntarily taken the stand, petitioner was under an obligation to speak truthfully and accurately, and the prosecution here did no more than utilize the traditional truth-testing devices of the adversary process.2 Had *226inconsistent statements been made by the accused to some third person, it could hardly be contended that the conflict could not be laid before the jury by way of cross-examination and impeachment.
The shield provided by Miranda cannot be perverted into a license to use perjury by way of a defense, free from the risk of confrontation with prior inconsistent utterances. We hold, therefore, that petitioner’s credibility was appropriately impeached by use of his earlier conflicting statements.
Affirmed.
Me. Justice Black dissents.
No agreement was reached as to the first count. That count was later dropped by the State.
If, for example, an accused confessed fully to a homicide and led the police to the body of the victim under circumstances making his confession inadmissible, the petitioner would have us allow that accused to take the stand and blandly deny every fact disclosed to the police or discovered as a “fruit” of his confession, free from confrontation with his prior statements and acts. The voluntariness of the confession would, on this thesis, be totally irrelevant. We reject such an extravagant extension of the Constitution. Compare Killough v. United States, 114 U. S. App. D. C. 305, 315 F. 2d 241 (1962).