BACKGROUND: Research on optimal timing of bilateral anatomic total shoulder arthroplasty (TSA) is lacking. The purpose of this study was to investigate functional outcomes in patients undergoing bilateral anatomic TSA to understand the ideal timing for the second arthroplasty. METHODS: Patients who underwent bilateral TSA for osteoarthritis between 2000 and 2012 with a minimum follow-up of 12 months since their most recent surgery were evaluated. Postoperative patient-reported outcomes (University of California-Los Angeles [UCLA] shoulder rating scale, Constant score, and Simple Shoulder Test [SST]), biometrics (strength and range of motion), and a subjective questionnaire were compared for 4 "interval groups" based on timing between surgeries: <6 months, 6 to 12 months, 12 to 24 months, and >24 months. RESULTS: Eighty-two shoulders (41 patients, 70 +/- 9 years old) were analyzed. Mean postoperative UCLA, Constant, and SST scores were 29, 72, and 9 points, respectively; 83% of patients reported satisfaction with both shoulders. Patients with <6 months between surgeries demonstrated significantly better UCLA scores than 6- to 12-month interval patients (P = .04), greater Constant scores compared with all other groups (P < .001), and greater SST scores compared with 6- to 12-month and 12- to 24-month interval patients (P = .002), with no differences in length of follow-up between groups. CONCLUSION: In the absence of extrinsic factors, such as convenience, changes in social support structure, or changes in health status, patients may be advised that having the second surgery within 6 months of the first might optimize their postoperative functional outcomes and satisfaction compared with waiting a longer interval between surgeries.