The study examined multiple dimensions of social support as predictors of depressive symptoms among a highly vulnerable population. Social network analysis was used to assess perceived and enacted dimensions of support (emotional, financial, instrumental), network conflict, closeness, and composition. Participants were 393 current and former injection drug users who were 72% less than or equal to poverty level, 96% African American, 39% HIV seropositive. At baseline, 37% had high depression scores (CES-D greater than or equal to 16). Adjusted logistic regression indicated that for every additional network member providing financial support, the odds of probable depression 1 year later decreased by 23%, and for every additional conflictive network tie the odds of depression increased by 57%. Findings suggest the greater importance to this population's psychological well-being of received support specific to environmental demands, rather than support perceived potentially available. The findings suggest potential directions for intervention. (Contains 3 tables.)