Previous studies have indicated that there is a significant prevalence (50%) of hypogonadism among men with acquired immunodeficiency syndrome (AIDS)-associated wasting, and for these patients testosterone administration has been shown to increase lean body mass and improve quality of life. However, the prevalence of hypogonadism is not known among men with weight loss related to human immunodeficiency virus (HIV) infection who are receiving highly active antiretroviral therapy (HAART). From 1997 through 1999, we investigated total and free testosterone levels in 90 men who were <90% of ideal body weight or had weight loss of >10% from preillness weight; 71% of these subjects were receiving HAART. Twenty-one percent of the subjects receiving HAART had low free testosterone levels. No correlation was seen between weight, CD4 cell count, medication status, and other clinical factors. These data suggest that hypogonadism remains relatively common in men with AIDS wasting, despite treatment with HAART. HIV-infected men with wasting syndrome should be screened for hypogonadism and receive physiological androgen replacement therapy if they are hypogonadal.