This research proposal requests 3 years of support to conduct developmental intervention studies to design and field test a theory-based intervention to address food insecurity and improve antiretroviral therapy (ART) adherence among men and women living with HIV infection. Food insecurity is prevalent among people living with HIV in US inner-cities, with as many as 43% not having sufficient food and experiencing intermittent hunger. Food insecurity has demonstrated direct associations with ART adherence including predicting non-adherence over and above other factors including depression, social support, and alcohol use. Food insecurity is particularly problematic in relation to substance abuse given competing survival needs and the dire combined health consequences of alcoholism, addiction and malnutrition. Guided by the Conservation of Resources Theory of Stress and Coping, we will conduct 3 stages of intervention development research: (1) initial interviews and focus groups with people living with HIV who take ART, use substances, and experience food insecurity. Based on information gained from rapid formative studies, this first stage of research will be used to develop a theory-based intervention to address accessing food and sustaining ART adherence; (2) Test the feasibility of the newly developed food insecurity and adherence intervention with a small sample of HIV positive men and women who are taking ART, use substances, and experience food insecurity. Stage 2 will also finalize and pilot test all assessment instruments and protocols for data collection; and (3) Conduct a randomized field test to determine the potential efficacy of the food insecurity and ART adherence intervention. Participants in the field test will be randomly assigned to either receive the newly developed intervention or a time matched attention comparison condition. Following a 6- month follow-up period, we will test for differences between groups on ART adherence, food access, nutrition, and coping resource outcomes. The intervention development will include pilot testing daily food, mood, and substance use behaviors monitored by interactive text-message surveys. We will also examine the intervention effects on mediating theoretical constructs derived by Conservation of Resources Theory. Our developmental research will also examine the feasibility and acceptability of conducting the intervention in face-to-face intervention sessions. The proposed intervention research will therefore develop new strategies for use with people living with HIV who are taking ART under adverse conditions with multiple competing needs.