The authors examined data from a large cohort of HIV-infected persons to demonstrate recent trends in wasting syndrome, to examine the influence of wasting syndrome on the incidence of other opportunistic illnesses, and to explore if any of the commonly prescribed treatments for wasting are associated with improved survival. Kaplan-Meier analysis and multivariate left-truncated Cox models were used to estimate time to death after the first diagnosis of wasting syndrome and to quantify the association between the covariate and mortality, respectively. The incidence of wasting declined during 1992 through 1999, with the most marked rate of decline occurring after 1995. The incidence of AIDS- and non-AIDS-defining illnesses was generally high at or after a diagnosis of wasting syndrome. Factors significantly associated with improved survival include having a CD4+ count of > or =200 cells/L during the interval of the wasting syndrome diagnosis and antiretroviral therapy with two or more drugs at or after the diagnosis of wasting syndrome. Prescription of oxandrolone was associated with improved survival, but the results did not quite reach statistical significance. The authors' study provides supportive information that treatment of wasting syndrome may have a favorable impact on survival.