Vaginitis is a common gynecologic disorder that is responsible for 10 million office visits to physicians each year. Infectious vaginitis is the most common cause of a vaginal discharge, but other important diagnostic considerations include infectious cervicitis, a physiologic discharge, atrophic vaginitis, and allergic or irritant vaginitis. Although the history and gynecologic examination may suggest the diagnosis, laboratory confirmation should be routinely sought by performance of the vaginal pool wet mount examination, the amine whiff test, determination of the vaginal pH, and the Q-tip test. Once a precise diagnosis is made, effective therapy can then be prescribed. For patients with Candida vaginitis, therapeutic options include either the vaginal administration of a number of available imidazole or triazole antifungal agents or the prescription of the oral triazole agent fluconazole. Oral metronidazole remains the only effective treatment for trichomoniasis in the United States. Bacterial vaginosis, which has been linked to a number of obstetric and gynecologic complications, is effectively treated with oral metronidazole, although vaginal metronidazole gel and oral and vaginal clindamycin formulations are available as well.