Our objective was to investigate the relationship between body mass index (BMI) and operative time (OT) for benign hysterectomy and determine if BMI with or without other clinical factors can predict OT to better utilize operative room scheduling. This was a secondary analysis of women undergoing laparoscopic, abdominal, or vaginal hysterectomy between 2014-2019 using the American College of Surgeons National Surgical Quality Improvement Program database (NSQIP), N = 117,691. Hysterectomies performed for cancer were excluded. BMI was defined as a continuous variable, and our primary outcome was log10 transformed OT. Multivariable linear regression was used to analyze the relationship between OR time and BMI with covariates including age, uterine weight, route of hysterectomy, smoking status, parity, prior pelvic and abdominal surgery, endometriosis, and subspecialty performing the surgery. A predictive model using 16 variables that could be reliably obtained preoperatively was initially created. A parsimonious model that would be more easily used was selected by including only variables that accounted for >10% of the total Eta2 (i.e., the sum of the proportion of variance associated with all effects included). The final reduced model included only BMI, age divided into quintiles, and route of hysterectomy. Within NSQIP database, route of hysterectomy was 22% abdominal (AH), 16% vaginal (VH), and 62% laparoscopic (LH). The mean OTs were 144, 133, and 158 minutes for AH, VH, and LH, respectively. Uterine weight >250g, prior abdominal surgery, and endometriosis were all statistically associated with increasing operative time; however, the relationship between BMI and operative time was not modified by these factors – the two-way interactions between those factors and BMI were not significant. Route of surgery is a modifier of OT when stratified by BMI; for every 10-unit increase in BMI, estimated OT increased by 9, 7, and 8 minutes for AH, VH, and LH, respectively. Neither the large model with 16 variables nor the concise model with 3 variables accounted for a large percentage of the total variability in log10(OT). R2 values 6.2% and 3.9% for full and reduced models, respectively. There is a positive correlation between BMI and OT for benign hysterectomy across all routes of surgery. Increasing BMI differentially impacts the OT in AH greater than LH and VH. Operative time for hysterectomy is highly variable and its estimation based on patient characteristics and other preoperative variables is difficult to reliably predict.