Abstract
The effect of serum from patients with severe chronic renal failure on the motility of ejaculated spermatozoa was objectively evaluated by the multiple exposure photography method. Uremic serum was not found to have a deleterious effect on the motility of ejaculated spermatozoa. On the contrary it caused a significant increase of spermatozoal velocity and a slighter increase in the percentage motility. These effects cannot be only attributed to the lowering of seminal viscosity and to the reduction of sperm concentration, but to various substances contained in blood serum.