Jose Angel Castoreña, federal prisoner # 23875-077, appeals the denial of his mo *182 tion for reduction of sentence under 18 U.S.C. § 3582(c)(2). He argues that he is entitled to a reduced sentence under Amendment 505 to the Sentencing Guidelines and the Supreme Court’s decisions in Blakely v. Washington, 542 U.S. 296, 124 S.Ct. 2531, 159 L.Ed.2d 403 (2004), and United States v. Booker, 543 U.S. 220, 125 S.Ct. 738,160 L.Ed.2d 621 (2005).

A district court exercises sound discretion in determining whether to grant a 18 U.S.C. § 3582(e)(2) motion, and we review its decision for abuse of discretion only. United States v. Gonzalez-Balderas, 105 F.3d 981, 982 (5th Cir. 1997). The district court did not abuse its discretion in denying Castorena’s motion. This court’s previous opinion denying relief under § 3582(c)(2) with respect to Douglas’s Amendment 505 claim is the law of the case. See United States v. Becerra, 155 F.3d 740, 752 (5th Cir. 1998). Castorena’s Blakely and Booker claims are not cognizable in the context of a 18 U.S.C. § 3582(c)(2) motion because neither case is based on a retroactive amendment to the Guidelines. See United States v. Shaw, 30 F.3d 26, 29 (5th Cir. 1994).

AFFIRMED.