The semen quality of 21 Medical students who produced sperm by masturbation has been assessed. The mean density of 21 samples examined on the first day was 64,4 millions per millilitre, while that on the third and fifth day of the study period were 52.2 and 50.7 millilitre respectively. This showed a statistically significant difference between the first and the third samples. Another statistically significant difference (P less than 0.5) was demonstrated in the semen volume of the first and third, and the third and fifth samples respectively. Significant differences were, however, not observed in the motility and morphology changes in the group samples. We therefore conclude that even though repeated semen ejaculations on alternate days do affect the density and volume of the semen, the most important overall effect is not such as to impair the potential fertility of the man who has normal initial sperm characteristics.