This project examines the effects of Comprehensive School Reform (CSR) models on the achievement of students in Kentucky middle schools. Previous studies exploring the effects of CSR on schools and student achievement have rendered mixed results (Berends, 2000; May & Supovitz, 2006; May, Supovitz, & Perda, 2004; RAND, 2002; Zhang, Shkolnik, & Fashola, 2005). The project examines student achievement in 74 schools identified as "low performing" in 1998-99 by the Kentucky Department of Education. It employs least squares regression to analyze data from the 2002-03 academic year, four years after 18 of the schools had implemented CSR models. Findings suggest that the impact of CSR was minor. Students in schools that had applied but did not receive CSR funding consistently scored higher than those in other comparison schools, whereas students in the CSR-funded schools performed the same or lower than those in comparison groups. These findings hold important implications for policy makers, model providers, and educators as they attempt to clarify the effects of CSR models on achievement among middle school students. (Contains 6 tables and 1 footnote.)