Computer-assisted sperm movement analysis was used to study the effect of pentoxifylline on human sperm motility characteristics and motility longevity of postthaw cryopreserved semen. This study focused on the following issues: the changes in individual movement characteristics in response to pentoxifylline, the persistence of the response during drug treatment. Computerized analysis was started at 30 min, 3 hrs and 24 hrs, after addition of pentoxifylline. Data obtained showed that pentoxifylline significantly increased percentage of sperm motility, average path velocity (VAP), curvilinear velocity (VCL), straight line velocity (VSL), amplitude of lateral head displacement (ALH) at two of the three time periods (p < 0.05). But, it did not significantly increase linearity (LIN), straightness (STR), and beat cross frequency (BCF) at any time. After 24 hrs, all motility variables were significantly decreased in both groups. However, the 24-hr motility longevity in the treatment group was greater than that of the control group. The present analysis shows interest in the use of pentoxifylline as a sperm movement enhancer for postthaw cryopreserved semen. It shows a beneficial effect in the majority of sperm movement parameters and motility longevity which may increase pregnancy rates after insemination. However, whether this change leads to an increase in fertilizing ability requires further study.