The present review identifies elements that are essential to the treatment of erectile dysfunction and andropause; the factors that should be gleaned from patient history and physical findings to help to define which disorder is most likely to be the cause of a patient’s concerns; and what treatment options exist. The major diagnostic approaches that should be undertaken for the comprehensive evaluation of the male patient with androgen deficiency of the aging male or erectile dysfunction are highlighted. Determining which condition is present is essential for optimal patient management.