Background: Mothers giving birth by non-elective cesarean section have considerably higher risk of developing postoperative infection, than mothers giving birth by elective cesarean section. Meta-analyses have shown that the risk of infection is reduced when administering antibiotics at least 30 min prior to skin incision rather than after cord clamping. If given prior to incision, antibiotics are present in the neonatal bloodstream for up to 24 h after delivery, with early exposure to antibiotics potentially disturbing development of the gut microbiome. We aimed to retrospectively assess the prevalence of postoperative infection after non-elective cesarean section at a single labor ward administering antibiotics after cord clamping, additionally investigating risk factors for developing postoperative infections. Methods: In this retrospective cohort study, we included a total of 2,725 women giving birth by non-elective cesarean section in 2010–2017 with a review of records for prenatal risk factors, labor management, and perinatal outcomes. The primary outcomes were a main composite infection of development of either endometritis, surgical-site infection, or sepsis in conjunction with a relevant antibiotic prescription. Secondary outcomes included infection of unknown focus, mastitis, urinary tract infection, and pneumonia. Results: A total of 88 patients developed a main composite infection (3.2%). These infections subdivide into endometritis (n = 37/2725, 1.4%), surgical-site infection (n = 35/2725, 1.3%) and sepsis (n = 15/2725, 0.6%). We found a high body mass index (aOR = 3.38, 95%CI 1.93–5.92) and intrapartum fever (aOR = 2.26, 95%CI 1.22–4.59) to be independent risk-factors for developing postoperative infection after non-elective cesarean section. Furthermore, we found delivery by a more expedient emergency grade 2 cesarean section (aOR = 0.61 95%CI 0.37–0.998) compared to grade 3 to be a protective factor for developing postoperative infection after non-elective cesarean section. Conclusion: In a labor ward administering antibiotics after cord clamping at non-elective cesarean births, we find a low prevalence of main composite infections when compared to estimates from meta-analyses on the topic. We conclude that administration of prophylactic antibiotics after cord clamping appears to result in acceptable rates of postoperative infection and avoids transplacental-transmission of antibiotics to the infant.