: The purpose of this study was to examine the effects of gender and cooperative learning with CAI on college students' computer science achievement and attitudes toward computers, when the effects of computer ownership, prior computer instruction, previous software and programming experience were controlled. The participants were 155 undergraduates enrolled in introductory computer courses at two colleges in North Taiwan during the Fall 1996 semester. Before the treatment period, they were asked to fill out the Background Data Form, instructed with cooperative learning strategy, and trained on cooperative and individual learning with CAI. During the treatment period, they were randomly assigned to the treatment (78 students) or the control group (77 students). The treatment group students used a CAI program on computer numbering, encoding, and hardware systems with their partner throughout all six CAI sessions. The control group students used the same CAI program individually within the six CAI sessions. After the 6-week treatment period, both groups were posttested by a 40-item multiple-choice Computer Science Achievement Test (CSAT) and a 30-item Computer Attitude Scale (CAS). Data for both posttests were collected from 153 students (77 in the treatment, 76 in the control group; 62 males, 91 females) and analyzed by MANCOVA and follow-up univariate hierarchical MRC analyses for ANCOVAs.