The use of lectures for motivational purposes and to stress the written word were original components of the personalized system of instruction (PSI). These features assume that students have the study skills to acquire information on their own. We investigated the relation between reading ability and course performance in PSI and contingency managed lecture (CML) sections of a developmental psychology course. Results indicated that grade point average (GPA) and reading comprehension scores best predicted final exam performance in CML and that reading comprehension scores and GPA were the best predictors in PSI sections. Students in the PSI and CML sections achieved average reading scores and vocabulary subtest scores at or above grade level, but average reading rate and comprehension subtest scores were below grade level.