Hypogonadism is well documented in HIV-infected men, particularly as they progress to AIDS and in those with symptoms of wasting. Testosterone deficiency can be diagnosed with simple laboratory tests, and various treatment options exist. The benefits of androgen replacement are well documented from a large body of literature and experience with hypogonadal men without HIV infection. Hypogonadal men who are given testosterone replacement have improved sexual thoughts and functioning, more energy, and improved mood. Generally, quality of life improves with such therapy. Testosterone replacement tends to maintain or improve lean body mass. The benefit, dose, and timing of testosterone replacement treatment for men with HIV infection, however, are less clear and require further study. Appropriate history and a high degree of clinical suspicion, coupled with relatively simple laboratory measurements, can confirm the diagnosis of hypogonadism in men with HIV. Various options for testosterone replacement, including injections of testosterone esters and the use of transcutaneous patches, are discussed, as are the uses of pharmacologic doses of testosterone, primarily for its potential anabolic effect.