This study assessed how women's perceptions of emotional and material social support affect their completion of residential drug treatment. Although previous research has examined how social support affects recovery, few studies, if any, have examined both the types and the sources of social support. The study hypothesized that women's perceptions of the emotional and material social support they receive from family, friends, partners, drug treatment, child welfare, and welfare agencies will affect treatment completion. The sample consisted of 117 women who were enrolled in a women's residential treatment program. Data were collected in semistructured initial and follow-up interviews using a life history calendar; the Scale of Perceived Social Support, which was adapted for this study; and women's treatment records. The results support the hypothesis. Social support can have both positive and negative effects on treatment completion, depending on the type and source of support provided.