The number of couples seeking consultation for infertility problems has steadily increased over the past decade, affecting 10%-15% of the sexually active population. Abnormal semen production, a male factor infertility (MFI), is thought to be the cause of up to 50% of all infertilities in developed countries. There are potentially many different causes of male infertility, including hormonal, anatomical, and secondary to exposure to exogenous substances. In many cases of MFI, a definitive cause for abnormalities is never identified. Recently, the research community has given greater attention to identifying causes of MFI ranging from genetic Y chromosome microdeletions to mechanisms of environmental damage on sperm production. Still evolving, is a clear understanding of how many pharmaceutical medications may cause MFI, which is often treatable and reversible. In this review we will out-line the data regarding various pharmaceutical medications that have been investigated as possible causes of MFI.