Dermatologic diseases of the genitalia are of several types: congenital diseases, acquired diseases (those caused by viruses, bacteria, fungi, or physical or chemical toxins), tumors, and atrophic dermatoses. The methods available to diagnose these diseases vary. Some conditions may be recognized by appearance alone, whereas others require histopathologic examination of involved skin for correct diagnosis. Some do not need treatment, while others call for an aggressive approach. Some types of genital dermatologic diseases, such as herpes infections and condylomata acuminata, appear to be associated with genital carcinogenesis. Patients with these diseases should be carefully examined.