Controversy exists concerning the exact role of genitourinary tract infections in male infertility. This ambiguity is due to the currently conflicting literature coupled with present limitations in obtaining and evaluating the significance of diagnostic tests such as semen cultures and leukocyte counts. In the evaluation of the infertile man for a possible infectious cause, a complete history, physical examination, and urinalysis identify most infectious disorders. In the majority of infertile men who are asymptomatic, evaluation for a subclinical genital tract infection focuses on the accurate determination of seminal leukocytes. The determination of pyospermia may identify those men with a subclinical genital tract infection who require further investigation. Prospective studies using clearly defined criteria, new diagnostic tools, and effective control groups are needed to evaluate better the impact of infection and pyospermia on male infertility.