Background/objectives: Studies on environmental exposure to toxic metals and their effects on male reproductive function are scare in our setting. This study evaluates the levels of lead and mercury in seminal plasma of infertile males who are non-occupationally exposed in Benin City, Nigeria and to determine the relationship between seminal quality and these toxic metals. Materials and Methods: A total of 80 subjects participated in this study which includes 60 infertile males on routine visit to the infertility clinics in Benin City and 20 fertile males as controls. The concentration of lead in seminal plasma was assayed by atomic absorption spectrophotometer while the concentration of mercury was measured using inductively coupled plasma Mass spectrometry. Semen analyses were performed using standard techniques as recommended by World Health Organization. Results: Mean seminal plasma lead and mercury levels were significantly higher (p<0.001) in infertile males compared with controls. Mercury and lead correlated negatively (p<0.001) with sperm count, progressive motility, total motility and morphology but not with semen volume. There was no significant correlation between toxic metals and sperm indices in fertile males (controls). Conclusion: The levels of the studied toxic metals were higher in seminal plasma of infertile males and appear to have adverse effect on seminal indices in non -occupationally exposed males.