To study the frequency of nail changes in a population of human immunodeficiency virus (HIV)-infected patients and to evaluate the specificity of these findings by comparison with HIV-negative control subjects. Prospective controlled study. Nail changes were recorded by a standardized clinical examination (curvature, nail plate, color, onychomycosis). In case of clinical diagnosis of onychomycosis, mycological culture was performed. Primary care university hospital. A total of 155 HIV-1-positive patients and 103 healthy HIV-negative control subjects of comparable age and sex ratio. None. Clinical examination findings. Nail symptoms were present in 67.7% of HIV-positive patients vs 34.0% of controls (P << .001). The following symptoms were significantly more frequent in the HIV group: clubbing (5.8%) (P < .05), transverse lines (7.1%) (P < .01), onychoschizia (7.1%) (P < .05), leukonychia (14.3%) (P < .001), and longitudinal melanonychia (14.8%) (P < .01). The main finding was onychomycosis in 30.3% of patients vs 12.6% of controls (P < .001). Trichophyton rubrum was present in 48% of onychomycoses and unusual Candida species were also recorded. Multiple fungi were frequently cultured in a single patient. The mean CD4+ cell count was lower in patients with onychomycosis and the frequency of onychomycosis increased in advanced stages of HIV disease. Acquired total leukonychia of the 20 nails was present in 4% of patients. Nail symptoms are much more frequent in patients with HIV than in healthy controls, and some of them could be linked to the level of immunosuppression.