Larry White appeals the sentence imposed following his guilty-plea conviction of distribution of cocaine base. White was sentenced to 120 months of imprisonment and three years of supervised release.

White asserts that the district court erred in its determination of the quantity of drugs attributable to his offense. The Government has moved for summary affirmance on the ground that White has waived his sole issue on appeal. Alternatively, the Government seeks an extension of time to file a brief.

Prior to sentencing, White objected to the presentence report, raising the same issue he presents on appeal. White, however, withdrew his objection at his sentencing hearing. “[Wlaiver is the ‘intentional relinquishment or abandonment of a known right.’ ” United States v. Olano, 507 U.S. 725, 733, 113 S.Ct. 1770, 123 L.Ed.2d 508 (1993) (quoting Johnson v. Zerbst, 304 U.S. 458, 464, 58 S.Ct. 1019, 82 L.Ed. 1461 (1938)). The withdrawal of an objection constitutes the waiver of the objection by the defendant. United States v. Musquiz, 45 F.3d 927, 931 (5th Cir. 1995). Accordingly, White’s challenge to the district court’s determination of drug quantity is unreviewable.

The Government’s motion for summary affirmance is GRANTED, its alternative request for an extension of time is DE *830 NIED as unnecessary, and the decision of the district court is AFFIRMED.