Candidiasis is the most common oral fungal infection seen in association with HIV infection. It may present in a number of clinical forms, including pseudomembranous and erythematous candidiasis. To determine whether erythematous candidiasis, like the pseudomembranous form, is predictive of the development of AIDS, we reviewed the records of 169 HIV-seropositive patients seen at clinic of the Oral AIDS Center, University of California, San Francisco who were diagnosed with pseudomembranous or erythematous (or both) forms of oral candidiasis at their first examination. Kaplan–Meier analysis showed a rapid rate of progression to AIDS (median, 25 months) and to death (median, 43.8 months) in all three groups. We conclude that erythematous candidiasis is as serious a prognostic indicator as pseudomembranous candidiasis. Because the erythematous form is more difficult to recognize and hence is underdiagnosed, efforts should be made to teach non-dental clinicians who care for HIV-infected patients to diagnose and treat this lesion.