The mainstay of the diagnosis of trichomoniasis has been the saline vaginal wet preparation. With a less than desirable sensitivity, the wet preparation may be replaced in the near future by newer methods employing monoclonal antibodies, such as the enzyme immunoassay, which has the potential to become an in-office procedure. The direct fluorescent antibody test also represents an advance in laboratory diagnosis. However, until the sensitivity, specificity, and cost of these newer techniques are defined outside the research arena, the wet preparation will remain the first-line diagnostic tool. Current treatment of trichomoniasis in the United States is with metronidazole, which in repeated or increased dosage can often overcome the organism's resistance to the drug. Other treatments offer little or no chance for cure but may provide some relief of symptoms. Tinidazole (not available in the United States) may be effective in curing refractory cases of metronidazole resistance. Metronidazole treatment during pregnancy should be resorted to only when absolutely essential.