Objective: The purpose of this study was to describe the incidence and risk factors for uterine sarcomas and parasitic myomas at the time of power morcellation., Study Design: We performed a retrospective review of 3523 women who underwent laparoscopic hysterectomy from 2001-2012. Univariate analyses were used for the morcellation cases to identify potential risk factors. Multivariable logistic regression was performed., Results: Nine hundred forty-one patients underwent power morcellation at the time of hysterectomy; 10 of 941 patients (1.1%) were diagnosed subsequently with uterine sarcomas or parasitic myomas. The overall incidence of uterine sarcoma was 6 of 941 (0.6%), with a median age of 47 years (range, 41-52 years). There was no association among any of the factors analyzed and uterine sarcoma. Three of 6 patients had sarcoma diagnosed on initial pathologic evaluation of the morcellated specimen; 3 patients had delayed diagnosis of sarcoma with benign disease at the time of the initial procedure (median time to second evaluation, 6 years). For parasitic myomas (n=4), the median age was 35 years (range, 32-40 years), and the median time to second evaluation was 5 years. On multivariate analysis, age<40 years (odds ratio, 26; 95% confidence interval, 2.7015-261.9; P≤.01) was associated with higher risk of the development of parasitic myomas., Conclusion: Uterine sarcoma was found in 0.6% of patients who underwent power morcellation but was not found to be associated significantly with any preoperative factors. All 6 cases were noted to have apparent fibroid tumors as an indication for their hysterectomy. Age<40 years was a risk factor for parasitic myomas after power morcellation. Patients should be counseled about these complications before power morcellation., (Copyright © 2015 Elsevier Inc. All rights reserved.)