Introduction. The objectives of the research are to determine the prevalence of major depression after childbirth and compare it with that of non-postpartum women; and to study the risk factors for postpartum depression. Method. We studied 425 women: 321 women in the first postpartum year, 41 nulliparous women and 63 women with more than 1 year postpartum. Results. The prevalence of major depression in the first postpartum year was 5.92%; this value was significantly lower than that of the women with more than 1 year postpartum. In women with less than 2 years postpartum we found less depression than in those with more than 2 years of delivery. The risk factors associated with postpartum depression found by logistic regression were: obsessive-compulsive disorder, premenstrual dysphoric disorder, previous major depression, maternity blues, young age and lower educational grade. Conclusions. Our study does not support the existence of a greater prevalence of major depression during postpartum in Peruvian women.