A meta-analysis of 19 studies was conducted to determine the magnitude of the effect of postpartum depression on maternal-infant interaction during the first year after delivery. Maternal-infant interaction was divided into three subcategories: maternal interactive behavior, infant interactive behavior, and dyadic interactive behavior. Substantive, methodological, and miscellaneous variables were extracted and coded by both the researcher and two research assistants. Combinations were calculated as unweighted, weighted by sample size, and weighted by the quality index score. Effects for maternal interactive behavior ranged from .32 to .36 for the r index, .68 to .78 for the d index, and .33 to .38 for the Fischer's Z. For infant interactive behavior, effects ranged from .35 to .38, .75 to .83, and .37 to .41 for the r, d, and Fisher's Z indexes, respectively. Effects for dyadic interactive behavior ranged from .47 to .50 for the r index, 1.07 to 1.15 for the d index, and .51 to .55 for Fisher's Z. Results of the meta-analysis indicate that postpartum depression has a moderate to large effect on maternal-infant interaction. Nursing interventions for depressed mother-infant dyads during the first year after delivery are addressed.