While 85% of couples are able to conceive after one year of protected intercourse, approximately 15% of couples are unable to initiate a pregnancy without some form of assistance or therapy. These patients are said to be "primarily infertile." In approximately one-third of these couples, a male factor appears to be singularly responsible, and in an additional 20% both a male and a female factor can be identified. Therefore, a male factor is at least partly responsible for difficulties in conception in roughly 50% of these couples. It has been shown that the longer a couple remains subfertile, the worse their chance for an effective cure. In addition, many couples experience significant apprehension and anxiety after only a few months of failure to conceive. For these reasons, unduly prolonged unprotected intercourse should not be advocated before workup of the male is instituted. Although it has often been recommended that clinical evaluation be delayed until 12 months of unprotected intercourse has passed, we believe that the initial screening of the male should be considered whenever the patient presents with the chief complaint of infertility. This initial evaluation, however, should be rapid, noninvasive, and cost-effective. The most important part of the management of male infertility is the correct diagnosis. The use of standard techniques for evaluating medical problems in general, such as complete history, physical examination, and laboratory tests is essential for this purpose.