Each of three technicians made duplicate pipettings from forty-six semen specimens ofseven donors and filled two haemocytometer chambers from each pipette. The number ofspermatozoa in each of the four large corner squares of the chamber were counted and recorded separately for a total of 2208 counts on 552 chambers. An analysis of variance was made and the percentage variances were calculated. Marked variation was found in counts among technicians and in duplicate counts by the same technician.