Postpartum nonpsychotic depression is the most common complication of childbearing, affecting approximately 10-15% of women and, as such, represents a considerable health problem affecting women and their families. This systematic review provides a synthesis of the recent literature pertaining to antenatal risk factors associated with developing this condition. Databases relating to the medical, psychological, and social science literature were searched using specific inclusion criteria and search terms, in order to identify studies examining antenatal risk factors for postpartum depression. Studies were identified and critically appraised in order to synthesize the current findings. The search resulted in the identification of two major meta-analyses conducted on over 14,000 subjects, as well as newer subsequent large-scale clinical studies. The results of these studies were then summarized in terms of effect sizes as defined by Cohen. The findings from the meta-analyses of over 14,000 subjects, and subsequent studies of nearly 10,000 additional subjects found that the following factors were the strongest predictors of postpartum depression: depression during pregnancy, anxiety during pregnancy, experiencing stressful life events during pregnancy or the early puerperium, low levels of social support, and a previous history of depression. Critical appraisal of the literature revealed a number of methodological and knowledge gaps that need to be addressed in future research. These include examining specific risk factors in women of lower socioeconomic status, risk factors pertaining to teenage mothers, and the use of appropriate instruments assessing postpartum depression for use within different cultural groups.