In semen samples from 94 men from infertile couples and 42 control patients proven to be fertile the occurrence of different kinds of nonspermatozoal cells (NSC) was examined. The findings were evaluated in relation to other seminal parameters and to the fertility status of the couple. The ratios of NSC to sperm and primary spermatocytes to spermatids revealed increasing values with decreasing sperm counts. Especially in a group where the semen samples contained ≥6 10⁶ motile sperm per mL and no infertility factor was detectable in the woman, the concentration of leukocytes was high, with three of eight patients having ≥10⁶ leukocytes per mL. A high proportion of abnormal sperm seemed to occur more frequently where the cause of infertility could be found in the man. A high number of leukocytes was neither significantly associated to an increased proportion of abnormal sperm nor to sperm motility evaluated by recording the percentage of motile sperm and the 1-h migration distance in sodium hyaluronate medium. No correlation between concentration of lymphocytes and presence of antisperm antibodies in seminal plasma was detectable.