This study evaluated the positive predictive values of factors associated with Gardnerella vaginalis, Candida albicans, and Trichomonas vaginalis for diagnosing vaginitis in a community-based population. One hundred ninety-six women with and without vaginal complaints were evaluated for historical factors, physical examination findings, and office laboratory results that were potentially associated with each of the three vaginal organisms. Extensive microbiological tests were performed to detect pathogenic organisms in the vagina and cervix. Gardnerella vaginalis was associated with findings of clue cells, gray or creamy vaginal discharge, amine ordor on application of potassium hydroxide solution to the discharge, pH greater than 5, and a history of more than six sexual partners. Candida albicans was associated with the presence of pseudohyphae or budding yeast on microscopic examination and the lack of clue cells. Current use of oral contraceptives and the recent use of antibiotics were not predictive of a Candida albicans infection. Trichomonas vaginalis was more common in patients presenting with symptoms, but otherwise was not predicted by the factors tested.