Oral hairy leukoplakia (HL) is a lesion that occurs predominantly on the tongue in HIV-infected persons. Evidence strongly indicates that HL is related to the presence of Epstein-Barr virus in the epithelial cells. The lesion appears on the lateral border of the tongue as a painless, white plaque varying in size from a few millimeters to extensive lingual involvement. Histopathologically, the characteristic findings are hyperparakeratosis, hyperplasia, and ballooning of prickle cells resembling koilocytosis. HL is now considered a frequent, early, and specific sign of HIV infection and a strong indicator that AIDS will develop in the patient. We report on two cases of HL with marked oral mucosal involvement with extension to the pharyngeal mucosa.