Abstract Objective Increases in postpartum hemorrhage have been reported from several countries. We assessed temporal trends in postpartum hemorrhage and severe postpartum hemorrhage in Canada between 2003 and 2010. Methods We carried out a population-based cohort study of all hospital deliveries in Canada (excluding Quebec) from 2003 to 2010 (n = 2 193 425), using data from the Canadian Institute for Health Information. Postpartum hemorrhage was defined as a blood loss of ≥ 500 mL following vaginal delivery or ≥ 1000 mL following Caesarean section, or as noted by the care provider. Severe postpartum hemorrhage was defined as postpartum hemorrhage plus blood transfusion, hysterectomy, or other procedures to control bleeding (including uterine suturing or ligation/embolization of pelvic arteries). Temporal trends were assessed using the chi-square test for trend, relative risks, and logistic regression. Results Postpartum hemorrhage increased by 22% (95% CI 20% to 25%) from 5.1% in 2003 to 6.2% in 2010 ( P < 0.001), driven by a 29% increase (95% CI 26% to 33%) in atonic postpartum hemorrhage (3.9% in 2003 vs. 5.0% in 2010, P < 0.001). Postpartum hemorrhage with blood transfusion increased from 36.7 to 50.4 per 10 000 deliveries ( P < 0.001), while postpartum hemorrhage with hysterectomy increased from 4.9 to 5.8 per 10 000 deliveries ( P < 0.01). Postpartum hemorrhage with uterine suturing, or ligation/embolization of pelvic arteries, increased from 4.1 to 10.7 per 10 000 deliveries ( P < 0.001). These increases occurred in most provinces and territories, and could not be explained by changes in maternal, fetal, and obstetric factors. Conclusion Rates of postpartum hemorrhage and severe postpartum hemorrhage continued to increase in Canada between 2003 and 2010.