This study examined the relationships of stress and social support to maternal attitudes and early mother-infant interactive behavior. 52 mother-premature infant pairs and 53 mother-full-term infant pairs were seen for structured home interviews at 1 month, and behavioral interactions at 4 months. Maternal life stress, social support, life satisfaction, and satisfaction with parenting were assessed at the 1-month home visit. Although no group differences were found, both stress and support significantly predicted maternal attitudes at 1 month and interactive behavior at 4 months when data were pooled. Mothers with greater stress were less positive in their attitudes and behavior, while mothers with greater support were significantly more positive. Intimate support proved to have the most general positive effects. Additionally, social support moderated the adverse effects of stress on mother's life satisfaction and on several behavioral variables. Maternal social support was further found to have several significant effects on infant interactive behavior. Results are discussed in terms of the ecological significance of social support to parenting and infants' early development.