OBJECTIVE: To examine the association between antidepressant use and the likelihood of being employed among HIV-positive persons receiving highly active antiretroviral therapy (HAART). DATA SOURCES: Panel (longitudinal), semi-annual data (from 1996 to 2004) from the Women’s Interagency HIV Study (WIHS), a cohort study of 3,768 women in Bronx and Brooklyn (New York), Chicago (Illinois), Los Angeles and San Francisco (California), and Washington, D.C.; and the Multicenter AIDS Cohort Study (MACS), a cohort of 6,973 men in Baltimore (Maryland), Chicago (Illinois), Los Angeles (California), and Pittsburgh (Pennsylvania). METHODS: Regression analyses models of employment (linear, non-linear, and dynamic, under fixed and random effects assumptions), conditioning on the use of HAART at every prior calendar visit. The regressions control for: demographic characteristics (age, race, education); clinical indicators (CD4 cell count, viral load); physical and mental health summary measures (physical component of the SF-36 or quality of life index; and CES-D); and local area characteristics (unemployment rate, real weekly earnings, and employment ratios). Different measures of State Medicaid coverage for antidepressants are used as instrumental variables to predict antidepressant use independently of outcomes; thus, addressing potential sources of bias -- more depressed persons tend to receive antidepressant treatment, but they are also more likely to be unemployed. iii PRINCIPAL FINDINGS: The proposed instrumental variables can be used to identify antidepressant use in the WIHS population. Results show that antidepressant use has a positive effect on the employment probability of women living with HIV. Among women receiving HAART, and controlling for individual and local area labor market characteristics, use of antidepressants is associated with a higher probability of being employed. On the other hand, the proposed instruments do not perform well on the MACS sample. The treatment probability can be predicted only weakly. With the current instruments, we cannot find a positive effect of antidepressant use on employment for the participants in the MACS. CONCLUSIONS: Increasing efforts to improve screening, diagnosis, and treatment of depression in specific high-risk HIV positive populations, particularly low-income women, is warranted not only for the physical and mental health benefits, but also as an avenue to increase employment.