The purpose of this investigation was to determine the effects of multimedia computer assisted instruction (CAI) on teaching tennis Content Knowledge and Pedagogical Content Knowledge (PCK = Appropriate cues, feedback and demonstration) in a physical education teacher education (PETE) program. The data were obtained from 18 undergraduate PETE students enrolled in an evaluation and assessment course. Subjects were randomly assigned to three groups: CAI group (n=6), Teacher Instruction (TI) group (n=6), and Control (CG) group (n=6). The CAI group completed a sixty-minute instruction about teaching the tennis serve in a computer lab. Two multimedia CAI tutorials, Interactive Tennis (Petrakis, 1996) and Tennis Task Analysis (Petrakis & Konukman, 1999) were used. The TI group received a sixty-minute teacher instruction having the same content that was used in CAI tutorials. The control group received no instruction. The results of this study were gathered from the Tennis Serve Content Knowledge Test, two six minute micro teaching sessions on teaching tennis serve via observing video tapes and coding on Tennis Serve PCK Assessment Sheet. A pre-test and post-test experimental design was applied. The Kruskal-Wallis test was used to determine the differences among the three groups, and pairwise ranking with the Mann Whitney U test was conducted between all comparisons as a post hoc analysis. Moreover, the Wilcoxon Signed Rank test was used to determine pre-to post-test changes within the groups. Alpha set at p< 0.5. The results showed that although no significant differences were found between the TI and CAI groups (p>0.05), both groups performed significantly better than the CG group in tennis serve content knowledge (p<0.05) and only TI group improved significantly within the group (p<0.05). The TI group performed significantly better than the CAI and CG groups in providing appropriate cues. Only the TI group improved significantly within the group (p<0.05) and the CAI and CG groups did not improve (p>0.05). No significant differences were found among the groups in tennis serve PCK-Appropriate feedback (p>0.05). Finally, there were no significant differences between the TI and CAI groups in appropriate demonstration (p>0.05). However, both the TI and CAI groups performed significantly better than those in the CG group (p<0.05). Moreover, both the TI and CAI groups improved significantly within the group pre to post test (p<0.05). The CG group did not improve at all (p>0.05). The results of this study revealed that CAI can be an effective instructional method in certain areas.