Recently insulin resistance (IR) has been recognized as the underlying pathogenesis of chronic anovulation, hyperandrogenism, and metabolic abnormalities associated with PCOD in women. IR could be the underlying pathogenesis of chronic hypospermatogenesis leading to oligospermia and azoospermia associated with other metabolic abnormalities in men. Metformin has proven as an effective medication for not only IR but several other aspects of the PCOD including reproductive abnormalities. Therefore, insulin sensitizers, particularly metformin can be introduced as a pharmaceutical option for unexplained oligozoospermia and azoospermia associated with insulin resistance.