Vaginitis is a prevalent disorder requiring a thorough understanding by primary care physicians. An in-depth understanding of candidiasis, trichomoniasis and bacterial vaginosis provides the basis for effective treatment. An accurate initial diagnosis is needed in the evaluation of recurrent, chronic vaginitis. A simple office evaluation is usually sufficient and should include a careful microscopic evaluation of the vaginal secretions for hyphae, budding yeast forms, clue cells, trichomonads and Lactobacillus forms; a quantitative assessment of the white blood cells and non-Lactobacillus organisms; and an assessment of the presence of the newly described Mobiluncus species. Assessing the vaginal pH is also important in the evaluation. Vaginal cultures are necessary when the microscopic evaluation does not provide a clear etiology.