Sperm examination, quantitative sperm culture, citric acid, acid phosphatase, and fructose were assayed in three groups of men: fertile controls without significant bacteriospermia (group I), infertile men with significant bacteriospermia; idiopathic infertile men (group II), and infertile men with varicocele (group III). Level of significance of bacteriospermia was greater than or equal to 10(4) germs/ml of ejaculate. In group II, motility and typical morphology percentages were lower, independently of the degree and the nature of bacteriospermia. Incidence of pathogenic bacteria was higher than in group III and linked to the degree of bacteriospermia. Fructose was unaltered in the two groups of infected men. No modification of prostatic markers was observed in any groups, except in group II, where they decreased when bacteriospermia was lower than 10(5) germs/ml and when biological pattern of semen evoked chronic prostatitis. Thus, the presence of germs in ejaculate alters the motility and the typical morphology percentages but does not result in any obvious modifications of biochemical markers of prostate and seminal vesicles. For idiopathic infertile men, it is suggested that the quantitative criterion of pathogenic bacteriospermia is a germ count greater than or equal to 10(5)/ml.