OBJECTIVE: We sought to estimate the morbidity associated with regional anesthesia in morbidly obese women undergoing scheduled cesarean delivery. STUDY DESIGN: This was a retrospective cohort study of women undergoing elective scheduled cesarean delivery from September 2004 through December 2008. RESULTS: A total of 142 morbidly obese, 251 overweight and obese, and 185 normal-weight women met inclusion criteria. Differences between groups were identified regarding: complicated placement (5.6%, 2.8%, and 0%, respectively; P = .007), failure to establish (2%, 0%, and 0%, respectively; P = .047), and insufficient duration (4%, 0%, and 0%, respectively; P = .02) of regional anesthesia. The groups differed in the frequency of general anesthesia (6%, 0%, and 0%, respectively; P = .003), intraoperative hypotension (3%, 0%, and 0%, respectively; P = .01), and overall anesthetic complications (8.4%, 0%, and 0%, respectively; P < .0001). Prepregnancy body mass index > 40 kg/m(2) (receiver operating characteristic area under the curve, 0.856; positive likelihood ratio, 4.0) and delivery body mass index >= 45 kg/m(2) (receiver operating characteristic area under the curve, 0.877; positive likelihood ratio, 4.1) were predictive of anesthetic complications. CONCLUSION: Morbidly obese women have significant risk for anesthesia complications during cesarean delivery.