Objective: To identify risk factors for bladder injury during cesarean delivery, to let patients and doctors know them and their importance. Methods: We conducted a case-control study of women undergoing cesarean delivery at the Instituto Nacional de PerinatologiaIsidro Espinosa de los Reyes between january 2001 and december 2007. Cases were women with bladder injuries at the time of cesarean section. Two controls per case were selected randomly. Medical records were reviewed for clinical and demographic data to compare them. Results: Twenty-one bladder injuries were identified among 24, 057 cesarean sections, (incidence 0.087%), only 19 were analized. Prior cesarean section was more prevalent among cases than controls (63% vs 42% p 0.134), with an OR of 2.35 (95% CI 0.759-7.319), when we take only patients with one cesarea in contrast with no cesarea the OR is 3.75 (95% CI 1.002-14.07). Statistically significant differences (P values < .05) between cases and controls were found in gestacional age (38.16 vs 37.35 weeks), prior cesareans (42% vs 18%), adhesions (79% vs 5%), Odds ratio of 67.5 (95% CI 11.14-408), VBAC (31.5 vs 3%), median skin incision (16% vs 68%), Pfarmenstiel (84% vs 32%), blood loss (744cc vs 509cc) and length of surgery 135 vs 58 minutes). No differences were found among age, BMI, prior surgery, labor, premature rupture of membranes, station, chorioamnioitis, induction, uterine incision, timing of delivery, uterine rupture. Conclusion: Prior cesarean section and adhesions are risk factors for bladder injury at the time of repeat cesarean delivery. Elective cesarean delivery is valid but it is duty of physicians to inform patients the risks of it.