SUMMARY Background: Microorganisms can find the optimal conditions for survival in semen, causing damage to the spermatozoa and triggering processes of infertility or reproductive tract infections. Therefore, understanding the role of the microorganisms present in semen can help to improve the diagnosis of infertility cases where the only apparent cause is infectious processes. Objective: To describe and correlate semen parameters and bacterial growth in ejaculate. Methods: Identification of microorganisms isolated in 43 clinical spermocultures and 28 research spermocultures. We assessed colony-forming unit counts and sperm characteristics of research spermocultures. In addition, semen parameters were evaluated in each ejaculate. Results: Bacterial growth was obtained in 14 (32.6%) of the 43 clinical spermocultures and 15 (53.6%) of the 28 research spermocultures. The isolated microorganisms were Enterococcus faecalis, Escherichia coli, Morganella morganii, Staphylococcus coagulase negative, Klebsiella pneumoniae and mixed microbiota. Finally, in this study a large growth of aerobic cocci was observed. We did not find association between the decline in the quality of semen parameters and microorganisms. Conclusion: The presence of bacteria in semen does not affect semen quality.