Two studies examined the efficacy of using computer-assisted instruction (CAI) to supplement a phonics-based reading curriculum for preschoolers and kindergartners in an urban public school system. The CAI programs provided exercises in phonological awareness and basic phonics skills. We compared treatment classes using CAI with control classes receiving the same classroom instruction without CAI. For preschoolers, the treatment group made significantly greater gains than controls in phonological awareness. For kindergartners, treatment students with low pretest scores made significantly greater gains than controls, particularly in word reading. Overall, preschoolers and low-performing kindergartners benefited from intensive practice provided by CAI programs. (Contains 2 tables and 1 figure.)