Background: The effects of different sex hormones on urodynamics in female rabbits have been investigated previously. Estrogen induces an increase in bladder capacity and compliance, whereas testosterone and progesterone reduced bladder capacity and compliance. Objective: The aim of this study was to investigate the effects of sex hormones on bladder urodynamics in male rabbits. Methods: 5 groups were set up for the study: group I, low midline laparotomy (LML) + 0.9% NaCl; group II, LML + testosterone; group III, LML + bilateral orchiectomy (BO) + testosterone; group IV, LML + BO + progesterone, and group V, LML + BO + estrogen. Baseline urodynamic records and blood sex hormone levels were measured. In the follow-up all rabbits from each group underwent urodynamics 5, 10 and 30 days after injection. Estrogen, progesterone and testosterone levels were also measured during the follow-up period. For statistical verification Mann-Whitney U and Kruskal-Wallis χ<sup>2</sup> tests were used. Results: Hormone levels: Testosterone levels were found to be increased in groups II and III 5 and 10 days after the injection. Testosterone declined thereafter and returned to baseline levels on day 30. In groups IV and V progesterone and estrogen levels increased after the injection and returned to baseline levels on day 30. Urodynamics: In groups II and III testosterone increased the bladder capacity and compliance on days 5 and 10. In these groups, capacity and compliance decreased thereafter and returned to the baseline levels on day 30. These urodynamic findings correlated with the alterations in blood testosterone levels. In groups I and IV no changes were observed in bladder capacity and compliance. In group V capacity and compliance were found to be increased on day 5 after the injection and returned to baseline levels on day 30. The changes in bladder capacity were found to be statistically significant in groups II, III and V. Conclusion: In this study, after the injection of testosterone, bladder capacity and compliance increased with high blood testosterone levels in male rabbits. The most interesting finding was observed in the estrogen group, questioning the role of estrogens in males. These findings allow us to reconsider the role of sex hormones in bladder functions.