The relevant facts in this case are substantially as follows: In November 1962, Herman R. Testan and Naomi Testan (“the Testans”) filed a complaint in assumpsit against Allstate Insurance Company (“Allstate”) under the uninsured motorist provision of an automobile insurance policy issued by Allstate to the Testans. Allstate filed an answer and new matter going to the merits of the Testans’ right to recover under the policy, to which the Testans filed a reply. A certificate of readiness was filed and the case is presently near the top of the trial list.
On February 12, 1968, the Testans made a demand for arbitration with the American Arbitration Association, seeking to have arbitrated essentially the same facts and issues which were the subject matter of the aforesaid complaint in assumpsit. Allstate filed a petition and rule for preliminary injunction to enjoin the Testans from proceeding with arbitration before the American Arbitration Association, to which the Testans have filed preliminary objections.
There are presently before us two matters: (1) Allstate’s request for a preliminary injunction, and (2) the Testans’ preliminary objections to Allstate’s complaint requesting the preliminary injunction. Both matters raise the same legal issue, namely, whether *396the Testans are entitled to proceed with arbitration or whether they should be compelled to proceed with the assumpsit action previously instituted by them.
Allstate has averred various grounds in support of its position. It is not necessary, however, to discuss all of the grounds, since, in our opinion, one, namely, the doctrine of waiver, clearly supports Allstate’s position.
Where, as here, plaintiffs commence an action in assumpsit where they might have demanded arbitration, and where both sides have engaged in extensive pleadings, resulting in the filing of a certificate of readiness, and where, further, the case is ready for trial, we hold that the plaintiff cannot, five and a half years later, demand arbitration. Under the circumstances, we conclude that the Testans have waived their right at this late stage to demand arbitration.
For the foregoing reasons the preliminary objections of the Testans are hereby dismissed and, upon submission of an appropriate decree by counsel for Allstate Insurance Company, a preliminary injunction will be granted as prayed for.