This report describes a case of hairy leukoplakia in an HIV-infected child, and the treatment adopted. It was diagnosed by clinical and laboratory examinations, using exfoliative cytology (staining by the Papanicolaou method) and additional information was obtained by optical microscope analysis. In view of the lack of painful symptoms, of the innocuous nature of the lesion and large amount of medicines used by the patient, we decided to preserve and monitor the lesion.