Ordered that the judgment, as amended, is reversed, on the law, and a new trial is ordered. No questions of fact have been raised or considered.
The defendant was excluded from his Sandoval hearing, which was conducted in chambers. This constituted a violation of his statutory and constitutional right to be present at all "material stages" of his trial (see, US Const 6th, 14th Amends; N.Y. Const, art I, § 6; Snyder v. Massachusetts, 291 U.S. 97, 105-106; People v. Cain, 76 N.Y.2d 119; People v. Mehmedi, 69 N.Y.2d 759, 760-761; People v. Ciaccio, 47 N.Y.2d 431, 436-437). A Sandoval hearing is certainly one phase of trial during which the defendant's presence "has a relation, reasonably substantial, to the fullness of his opportunity to defend against the charge." (Snyder v Massachusetts, supra, at 105-106.) Accordingly, in People v Jenkins ( 157 A.D.2d 854), and People v. Peterson ( 151 A.D.2d 512) we held that a Sandoval hearing constitutes a material stage of trial, at which the defendant has a right to be present. There is no proof of an express waiver of this right in this case (cf., People v. Peterson, supra) and the error in excluding the defendant cannot be considered harmless (see, e.g., People v Cain, supra; People v. Mehmedi, supra). The judgment under review, as amended, must therefore be reversed, and we need not pass on any other issue including those raised in the defendant's supplemental pro se brief. Bracken, J.P., Sullivan, Harwood and Rosenblatt, JJ., concur.