This research investigates the effects of a planned program of computer assisted instruction on reading and language development of fourth grade students. The purpose of the study was to determine the effectiveness of microcomputer usage in supplemental reading and language instruction. Fifty-one matched pairs of fourth graders completed the one school year study. A t test for related samples was used to analyze the data. Multiple linear regression was used to allow a more detailed review of the basic data, including gender and entering ability. The findings include the following. 1. Post test scores for total reading or total language on the Comprehensive Test of Basic Skills of the experimental group did not differ significantly from the scores of the control group. 2. The incremental differences in the post test scores for the boys or the girls in the experimental group did not differ significantly from those of the boys or the girls in the control group in either reading or language. 3. For students starting lower, toward the middle or higher on the Comprehensive Test of Basic Skills total reading or total language, the relative progress of the experimental group of any of the three groups did not differ …