Introduction. To investigate the association of high Body Mass Index (BMI) with semen parameters and reproductive hormones in men of reproductive age. Setting. The Saudi Center for Assisted Reproduction. Method. This study was conducted during the period from February 2009 to February 2011. Subjects were exposed through medical history evaluation as well as physical examination. BMI was calculated. Two semen samples about 1 week apart were taken from each participant by masturbation after 2–5 days of abstinence. The samples were assessed according to the WHO Criteria. Blood samples (5 ml) were withdrawn; centrifuged and the resulting sera were preserved at −4 degrees Centigrade. Serum FSH, LH, PRL, and Testosterone levels were estimated by the ELISA method. Results. There was no significant correlation between BMI and any of semen and hormonal parameters. There was significant negative correlation between age and total motility. Only the advanced paternal age has shown significant association with low motility (P = 0.007). Conclusion. Our study showed a significant effect of aging on sperm motility and concentration.