Background: Ulnar collateral ligament (UCL) reconstruction is frequently performed in throwing athletes, but outcomes of UCL reconstruction requiring excision of bone, either within the substance of or replacing the UCL, have not been studied. Hypothesis: Clinical outcome for throwing athletes after UCL reconstruction with gracilis tendon will be less favorable for patients requiring concurrent excision of bone from within the substance of the UCL than for patients with no bone excision within, or replacing, the ligamentous anatomy. Study Design: Cohort Study; Level of evidence, 3. Methods: One hundred twenty pitchers of competitive levels between high school and major league who underwent UCL reconstruction using contralateral gracilis autografts completed a phone survey, and their medical charts were reviewed. Follow-up was a minimum of 2 years. Among the 120 patients, 42 (35%) had bone within, or replacing, the substance of the native UCL (bony group), and 78 (65%) had no bony abnormalities (nonbony group). The latter group of 78 underwent UCL reconstruction using gracilis tendon graft due to the absence of a palmaris longus tendon. Clinical outcomes were compared between the 2 study groups using t tests and x 2 analyses. Results: There were no statistical differences regarding time to return to throwing, time to return to competition, postoperative complications, or need for additional surgeries. The percentage of patients who returned to the same or higher level was higher in the nonbony group (91%) than in the bony group (81%), but this trend was not statistically significant (P = .083), likely due to a relatively small sample size. Changes in self-reported pitch control were different (P = .029) between the 2 groups, with a greater percentage of pitchers experiencing decreased control in the bony group. Conclusion: The presence of bone concomitant with UCL damage can lead to pitch control problems after UCL reconstruction and may also decrease the chance of return to play. © 2012 The Author(s).