Previous research has documented a substantial decline of standardized test scores of children from low-income backgrounds, relative to more advantaged peers, in later elementary grades, the so-called "fourth-grade slump." This article examines changes in reading achievement from first to fifth grade for students in a large urban school system with a high proportion of students from economically deprived backgrounds. Students received first-grade reading instruction from Direct Instruction (DI), Open Court, or a mixture of reading curricula. Results indicate that students in schools using DI had significantly greater gains in both reading vocabulary and comprehension than students in the two other settings and that their average levels of achievement in fifth grade were above the national norms, thus countering the fourth-grade slump. (Contains 8 tables and 8 footnotes.)