Objective. To evaluate the impact of Advanced Life Support in Obstetrics (ALSO) training on staff performance and the incidences of post-partum hemorrhage (PPH) at a regional hospital in Tanzania. Design. Prospective intervention study. Setting. A regional, referral hospital. Population. A total of 510 women delivered before and 505 after the intervention. Methods. All high- and mid-level providers involved in childbirth at the hospital attended a two-day ALSO provider course. Staff management was observed and post-partum bleeding assessed at all vaginal deliveries for seven weeks before and seven weeks after the training. Main Outcome Measures. PPH (blood loss ≥500ml), severe PPH (blood loss ≥1000ml) and staff performance to prevent, detect and manage PPH. Results. The incidence of PPH was significantly reduced from 32.9 to 18.2%[RR 0.55 (95%CI: 0.44–0.69)], severe PPH from 9.2 to 4.3%[RR 0.47 (95%CI: 0.29–0.77)]. The active management of the third stage of labor was also significantly improved. There was a significant decrease in episiotomies. By visual estimation, staff identified one in 25 of the PPH cases before the ALSO training and one in five after the training. A significantly higher proportion of women with PPH had continuous uterine massage, oxytocin infusion and bimanual compression of the uterus after the training. Conclusions. A two-day ALSO training course can significantly improve staff performance and reduce the incidence of PPH, at least as evaluated by short-term effects.