Sexually transmitted diseases are a persistent problem in the United States and throughout the world. Many of these infections involve the skin and may be encountered in the field of dermatology. This 3-part review highlights the cutaneous features, diagnosis, and treatment of 11 of the most commonly encountered sexually transmitted diseases, other than AIDS. However, this review does not cover sexually transmitted diseases such as chlamydia, which do not regularly have cutaneous manifestations. Part 1 focuses on syphilis, disseminated gonococcal infection, chancroid, lymphogranuloma venereum, granuloma inguinale, and genital herpes. Additional features, such as epidemiology and transmission of the organism, are discussed when applicable.