In Villa Guerrero municipality, floriculture is their first economic activity; there are intensively applied different pesticides alone and in mixtures. They fumigate every day, every second or third day, and men, women, children and third age people participate. The use of prohibited or restricted pesticides such as Tamaron, Temik and Curacron in agricultural activities brings health problems with them, especially in their reproductive health. The aim of this study was to determine whether occupational exposure to pesticides alters semen quality. It was held in an exposed group conformed by 30 male floriculturists and the non-exposed group were 30 university male students. All of the participants gave a semen sample and sign an informed consent. There was made a spermatobioscopy accord to the WHO/PAHO (2010). The spermiogram´s results in the exposed group showed: significant reduction in the sperm count, in the progressive fast and slow mobility as well as in the normal sperm average. On the other hand, there was a significant increase in the morphologic sperm abnormalities: big, small and double head; short, long and double tale, in comparison with the non-exposed group. Conclusion: it appears that the occupational exposure to pesticides changes the sperm quality.