To evaluate implementation of an enhanced recovery after surgery (ERAS) program for patients undergoing elective cesarean delivery by comparing opioid exposure, multimodal analgesia use, and other process and outcome measures before and after implementation. An ERAS program was implemented among patients undergoing elective cesarean delivery in a large integrated health care delivery system. We conducted a pre-post study of ERAS implementation to compare changes in process and outcome measures during the 12 months before and 12 months after implementation. The study included 4,689 patients who underwent an elective cesarean delivery in the 12 months before (pilot sites: March 1, 2015-February 29, 2016, all other sites: October 1, 2015-September 30, 2016), and 4,624 patients in the 12 months after (pilot sites: April 1, 2016-March 31, 2017, all other sites: November 1, 2016-October 31, 2017) ERAS program implementation. After ERAS implementation mean inpatient opioid exposure (average daily morphine equivalents) decreased from 10.7 equivalents (95% CI 10.2-11.3) to 5.4 equivalents (95% CI 4.8-5.9) controlling for age, race-ethnicity, prepregnancy body mass index, patient reported pain score, and medical center. The use of multimodal analgesia (ie, acetaminophen and neuraxial anesthesia) increased from 9.7% to 88.8%, the adjusted risk ratio (RR) for meeting multimodal analgesic goals was 9.13 (RR comparing post-ERAS with pre-ERAS; 95% CI 8.35-10.0) and the proportion of time patients reported acceptable pain scores increased from 82.1% to 86.4% (P<.001). Outpatient opioids dispensed at hospital discharge decreased from 85.9% to 82.2% post-ERAS (P<.001) and the average number of dispensed pills decreased from 38 to 26 (P<.001). The hours to first postsurgical ambulation decreased by 2.7 hours (95% CI -3.1 to -2.4) and the hours to first postsurgical solid intake decreased by 11.1 hours (95% CI -11.5 to -10.7). There were no significant changes in hospital length of stay, surgical site infections, hospital readmissions, or breastfeeding rates. Implementation of an ERAS program in patients undergoing elective cesarean delivery was associated with a reduction in opioid inpatient and outpatient exposure and with changes in surgical process measures of care without worsened surgical outcomes.