This article has focused on the evaluation of amenorrhea. Primary amenorrhea shares some diagnostic considerations with secondary amenorrhea. Having excluded these diagnostic considerations (pregnancy), the patient with primary amenorrhea should be further evaluated in consultation with an endocrinologist. Secondary amenorrhea is a common clinical complaint and an algorithm is proposed to guide the physician through the diagnostic evaluation. The evaluation is centered around excluding significant pathology in the central nervous system and evaluating for the common gynecological disorder of chronic anovulation. The clinical disorders of PCOS and hyperprolactinemia were discussed briefly, and the interested reader may obtain further information from the authors referenced in this article.