Opioids are used for pain control after total knee arthroplasty (TKA) and carry risk for abuse. Mandatory statewide databases have been created to monitor their use. The goal of this study was to identify patient risk factors for prolonged opioid use after TKA. The authors retrospectively reviewed a consecutive series of 676 primary TKA procedures performed between January 2017 and July 2017. Information on fulfillment of narcotic, sedative, benzodiazepine, and stimulant prescriptions was obtained from the Pennsylvania State Controlled Substance Monitoring website 6 months before and 1 year after the procedure. Bivariate and multivariate analyses were used to identify risk factors for the need for a second prescription and opioid use for longer than 6 months. Of this cohort, 30.3% used preoperative opioids, 60.5% filled a second opioid prescription, and 11.8% continued opioid use for longer than 6 months. Patients who had opioid use before the index procedure had more than 3-fold (odds ratio [OR], 3.29; P<.001) increased odds of filling a second opioid prescription and 8-fold (OR, 8.05; P<.001) increased odds of postoperative opioid use for longer than 6 months. Multivariate analysis was used to identify independent risk factors for requiring a second prescription, including discharge to a rehabilitation facility (OR, 2.77), bilateral procedures (OR, 1.88), preoperative narcotic use (OR, 1.70), and younger age (OR, 0.95). Independent risk factors for narcotic use for longer than 6 months included preoperative sedative (OR, 3.30) or narcotic use (OR, 1.49). This study identified several risk factors associated with prolonged narcotic use after TKA, including preoperative sedative use, and determined their relative weight. [Orthopedics. 2021;44(x):xx-xx.].Copyright 2020, SLACK Incorporated.