To determine the association between occupational pesticide exposure and semen quality among sprayers using organophosphate (OPs) pesticides, 31 pesticide sprayers and 80 men who were not exposed were studied. Semen and blood samples were obtained one day after last pesticide application. Semen samples were analyzed for sperm concentration, percentage of sperm motility, percentage of normal morphology, and fructose and zinc concentrations. Blood samples were analyzed for sex hormones. Pesticide sprayers had significantly reduced age-adjusted seminal volume, percentage of motility, percentage of sperm with normal morphology, serum luteinizing hormone, serum testosterone levels, and seminal zinc concentration (a marker of prostate function), as well as significantly increased time of liquefaction, seminal pH, percentage of immature sperm morphology, and leukocyte concentration. These findings provide further evidence that occupational exposures to OP pesticides adversely affect semen quality and sex hormones.