The study objectives were to (1) identify risk factors related to stress urinary incontinence (SUI) and postnatal depression (PD) after birth, and (2) investigate both possible directions of association between SUI and PD in population-based sample of Czech mothers. 3,701 nulliparous and multiparous women completed the self-reported questionnaires at 6 weeks and 6 months after birth and were included into the analyses of this prospective cohort study. Unadjusted and adjusted logistic regressions examined relationship between SUI a PD accounting for range of other risk factors. During the first 6 months after birth, 650 mothers (17.6%) developed SUI and 641 (17.3%) displayed signs of PD. The mode of delivery, parity and higher BMI were associated with SUI. The rate of PD symptoms was higher in mothers with positive history of prenatal depression, and in divorced or widowed mothers. Both conditions were associated with worse self-reported health, back pain and stop-smoker status. Initially, SUI at 6 weeks was slightly, but significantly associated with onset of PD at 6 months (OR 1.51, 95% CI 1.02-2.23) while PD at 6 weeks was not significantly related to new cases of SUI at 6 months (OR 1.48, 95% CI 0.91-2.39). After full adjustment these OR reduced to 1.41 and 1.38 (both non-significant), respectively. SUI and PD are common conditions in women postpartum that share some risk factors. Our study suggests that both directions of their relationship are possible although a larger study is needed to confirm our findings.