This study was designed to evaluate the effectiveness of a self-developed audio-tutorial (A-T) system in biology at the college level. The basic design of the study was a variation of a compromise experimental group-control group design. The control group was instructed by lecture-laboratory method, and the experimental by the A-T system. Facutal achievement and students' understanding of science were used as measures of effectiveness. Factual tests were used as pretests, used in weekly quizzes and again as part of a final examination. The Test on Understanding Science (TOUS) was used as a pretest and posttest. Other instruments used included: (1) Nelson-Denny Test scores, (2) Survey of Study Habits and Attitudes, and (3) a student questionnaire completed after the final examination. The A-T instructed group achieved at a higher level. No important between group differences were noted in growth in scores from pre-to-posttest for the TOUS instrument. A positive relationship was found between reading ability and academic achievement under both instructional methods. (Author/EB)