Repeat cesarean delivery (CD) accounts for approximately 15% of all annual deliveries in the US with an estimated 656,250 operations per year. We aimed to study whether prolonged operative time (OT; skin incision to closure) is a risk marker for post-operative maternal complications among women undergoing repeat CD. We conducted a cross-sectional retrospective study in a single tertiary center including all women who underwent repeat CD but excluding those with cesarean hysterectomy. Prolonged OT was defined as duration of CD longer than the 90th percentile duration on record for each specific surgeon in order to correct for technique differences between surgeons. Bi-variate analysis was used to study the association of prolonged OT with each one of the following maternal complications: post-operative blood transfusion, prolonged maternal hospitalization (defined as hospitalization duration longer than 1 week post-CD), infection necessitating antibiotics, re-laparotomy within 7 days post-CD, and re-admission within 42 days post-CD. A multivariate regression analysis was performed controlling for maternal age, ethnicity, parity, number of fetus, gestational age at delivery, trial of labor after cesarean, anesthesia, and number of previous CDs. The adjusted odd ratio was calculated for each complication independently and for a composite adverse maternal outcome defined as any one of the above. A total of 6507 repeat CDs were included; prolonged OT was highly associated (P value < 0.000) with: post-operative blood transfusion (4.4% vs. 1.5%), prolonged hospitalization (8.4% vs. 4.0%), infection necessitating antibiotics (2% vs. 1%), and readmission (1.8% vs. 0.8%) when compared to control. The composite adverse maternal outcome was also associated with prolonged OT (20.2% vs. 11.2%, p < 0.000). These correlations remained statistically significant in the multivariate regression analysis when controlling for confounders. Among women undergoing repeat CD, prolonged OT (reflecting CD duration greater than 90th percentile for the specific surgeon) is a risk marker for post-operative maternal complications.