INTRODUCTION: The chance of achieving a successful pregnancy through IVF-ET is limited despite recent scientific advances in this field due to several factors that are known to affect outcome. There are studies linking the presence of bacteria in male genital tract to poor semen parameters as well as IVF-ET outcome, results are however contradictory. In the presence of urethritis, treatment is warranted especially when dealing with infertile couples, but treatment of asymptomatic bacteriospermia that may possibly arise from contamination is controversial. It is against this background that this study is undertaken. AIM: To find out if seminal fluid bacterial isolate(s) affect the fertilization and clinical pregnancy rate in an IVF – ET procedure. METHODOLOGY: Is an analytical cross sectional study conducted at National Hospital Abuja IVF Centre between June 2017 and May 2018. All consecutive consenting eligible male partners of women undergoing IVF-ET treatment during the study period were enrolled. Detailed instructions were given to the patients concerning sterile techniques to prevent contamination of the seminal fluid. Samples were sent to laboratory for culture using 5% Blood agar, Chocolate agar, MacConkey agar, Columbia and Thayer Martins agar. Any growth of bacteria >10 000 colony forming units (CFU)/ml was considered significant and subsequently identified and tested for sensitivity to a panel of antibiotics. The influence of positive bacterial isolates on fertilization rate, biochemical pregnancy rate, clinical pregnancy rate (primary outcome), and multiple pregnancies were determined. Data was analyzed using SPSS version 22. Student’s t-test, Chisquare test and Fisher’s exact tests were employed as appropriate. P value < 0.05 at 95% confidence interval was regarded as statistically significant.