A comparison was made of three sperm separation techniques--direct swim-up, mini-Percoll, and Sephadex G-10--on semen parameters, including count, % motility, forward progression, and hypoosmotic swelling (HOS) test scores. Overall, the best quality sperm (less debris, best % and quality motility, and best HOS scores) were noted with the direct swim-up procedure. Mini-Percoll resulted in the highest count, but the worst HOS score. Sephadex G-10 resulted in quality of semen specimen almost as good as the direct swim-up procedure, but did allow some noncellular debris and bacteria to filter through the column.