The aim of this study was to assess the prevalence of oral leukoplakia (OL) in HIV-positive patients and to evaluate the clinical and histopathological features and the presence of Candida hyphae and viral infections (HSV 1, 2, HPV, EBV and CMV) by immunocytochemical methods using mono- or polyclonal antibodies. A total of 269 HIV-seropositive patients, (222 men, median age 36.7 years and 47 women, median age 32 years) were registered. OL occurred in 20/269 (7.4%) patients (men, smokers, median age 38 years); the non-homogeneous form was observed in 11%. A lesional biopsy specimen was obtained from 8/20 patients. Specimens did not show signs of epithelial dysplasia. Candida hyphae were evident in 2/8 cases. Two patients tested positive for HPV and CMV; antibodies against EBV, HSV1 and 2 were negative. In conclusion, the prevalence of OL is comparatively high in this group of HIV-seropositive patients (7.4% vs. 0.9-2.2%). Moreover, the mean age of the study group at the time of diagnosis for OL was lower (38 years vs. 60 years).