A meta-analysis of 44 studies was conducted to determine the magnitude of the relationship between postpartum depression and each of the following predictor variables: prenatal depression, history of previous depression, social support, life stress, child care stress, maternity blues, marital satisfaction, and prenatal anxiety. Effect sizes were calculated three ways: unweighted, weighted by sample size, and weighted by quality index score. Moderate to large significant effect sizes were revealed between these eight predictor variables and postpartum depression. The mean r effect size indicator range for each predictor variable was as follows: prenatal depression (.49 to .51), child care stress (.48 to .49), life stress (.36 to .40), social support (.37 to .39), prenatal anxiety (.30 to .36), maternity blues (.35 to .37), marital satisfaction (.29 to .37), and history of previous depression (.27 to .29).