Comprehensive testing has confirmed the ability of an electronic cell counter to determine the volumes of ejaculated and immature spermatozoa of bull, ram and boar. It was found that the modal volume of free cytoplasmic droplets in semen of these species was about one-third that of ejaculated, droplet-free spermatozoa. Electronic estimates of the volumes of spermatozoa with and without droplets, free droplets and separated heads and tail midpieces were consistent with one another; volumes found for heads and tail midpieces of bull spermatozoa were in agreement with the most reliable estimates made microscopically.