Objectives: Pituitary adenomas are common intracranial tumors (incidence 4:100,000 people) with good surgical outcomes; however, a subset of patients show higher rates of perioperative morbidity. Our goal was to identify relevant risk factors of postoperative complications or 30-day readmission following pituitary adenoma resection. Design: Retrospective database cohort study. Setting: National Surgical Quality Improvement Program (NSQIP) database Participants: Patients who underwent surgery for pituitary adenoma in 2006-2018. Main Outcome Measures: Patient complications and 30-day readmission rate Results: Among the 2,292 patients identified (mean age 53.3±15.9 years), there were 491 complications in 188 patients (8.2%). Complications and 30-day readmission have plateaued over time even as the number of cases have substantially increased. Unplanned readmission was seen in 141 patients (6.2%). Multivariable analysis demonstrated that hypertension (odds ratio [OR]=1.6, 95% confidence interval [CI]= 1.1, 2.1, p=0.005) and high white blood cell count (OR=1.08, 95% CI=1.03, 1.1, p=0.0001) were independent predictors of complications. Return to the operating room (OR=5.9, 95% CI=1.7, 20.2, p=0.0005), complications (OR=4.1, 95% CI=1.6, 10.6, p=0.004), and blood urea nitrogen (OR=1.08, 95% CI=1.02, 1.2, p=0.02) were independent predictors of 30-day readmission. Conclusion: We evaluated one of the largest datasets of pituitary adenoma to identify the perioperative factors most critical for dictating patient outcome. Several patient biomarkers, namely white blood cell count and blood urea nitrogen, may serve as preoperative markers that could potentially identify patients at higher risk. Control of blood pressure and renal disease may be perioperative management strategies that can impact outcome.