To assess the relationship between antiretroviral drug exposure and lipodystrophy, 69 human immunodeficiency virus type 1-infected patients receiving nelfinavir were investigated cross-sectionally. Lipodystrophy was defined by patients' self-report. Nelfinavir trough concentrations in plasma were significantly related to overall lipodystrophy and peripheral fat wasting scores and appeared to be an independent risk factor for lipodystrophy