Objective:To examine variables associated with hysterectomy-related complications, relative to surgical approach and other variables, that lead to readmission within 90 days of surgery.Methods:We conducted an observational cohort study for which data were extracted from electronic health records. Data were extracted of all patients (n = 3106) who underwent hysterectomies at 10 Kaiser Permanente Southern California medical centers between June 2010 and September 2011. Patients who were pregnant or had a cancer diagnosis were excluded from the study. To identify univariate associations between examined variables and procedure type, chi-square tests for categorical variables and t-tests or analysis of variance for continuous variables were used. Generalized estimating equations methods were used to test associations between independent variables and primary outcomes of interest. Statistical significance was determined using a p-value <.05.Results:Of 3106 patients, 109 experienced 168 post-operative complications. The most common post-operative complications were related to pelvic abscesses, bowel obstruction, or severe ileus, and the vaginal cuff. Pelvic abscesses were most frequent among total laparoscopic hysterectomy and total abdominal hysterectomy cases (p = .002), and vaginal cuff complications were most frequent among total laparoscopic hysterectomy cases (p = .015). Patients who underwent total vaginal hysterectomy (odds ratio = 2.13, confidence interval = 1.15–3.92), laparoscopic supracervical hysterectomy (odds ratio = 3.11, confidence interval = 1.13–8.57), and total laparoscopic hysterectomy (odds ratio = 5.60, confidence interval = 2.90–10.79) experienced increased occurrence of post-operative complications resulting in readmission. Other variables associated with an increased risk for readmission included high estimated blood loss (201–300 mL and 301+ mL, relative to 0–50 mL; odds ratio = 2.28, confidence interval = 1.24–4.18 and odds ratio = 2.63, confidence interval = 1.67–4.14) and long length of stay of 3 days or more (relative to 0 days; odds ratio = 2.93, confidence interval = 1.28–6.69). Pelvic specimen weight in the 151–300 g and 501+ g ranges appeared protective (odds ratio = 0.40, confidence interval = 0.25–0.64 and odds ratio = 0.54, confidence interval = 0.33–0.90). In a sub-analysis of 1294 patients, 74 hospital operative complications directly related to hysterectomy were identified among 59 patients. The most common hospital operative complications were excessive bleeding associated with surgery or injury to nearby structures. Among the sub-sample of 1294 patients, those with hospital operative complications were more likely to experience post-operative complications that lead to readmission (odds ratio = 3.82, confidence interval = 1.55–9.43, p = .004).Conclusion:The observed increased risk of complications among patients of Black race, who underwent laparoscopic supracervical hysterectomy or total laparoscopic hysterectomy, who experienced more than 300 mL surgical blood loss, who suffered hospital operative complications, and those whose hospitalization was 3 days or greater, offers an opportunity for higher scrutiny and preventive measures during usual hysterectomy care to prevent later readmission.