PURPOSE: To assess long-term clinical efficacy of uterine artery embolization (UAE) in young women and the clinical significance of patent artastomoses between uterine and ovarian arteries. MATERIALS AND METHODS: Consecutive women no older than 39 years of age treated with UAE for symptomatic uterine leiomyomata with at least 3 years of follow-up were included in the study. Analysis includes angiographic images, pre- and postoperative magnetic resonance (MR) images, and symptom evaluations. Clinical evaluation and symptom severity scores (SSSs) were obtained at 6 months and yearly. Leiomyomata volume change, SSS, and repeat intervention rates were compared for patients with and without anastomoses between uterine and ovarian arteries. RESULTS: The study cohort included 87 patients, including 30 white patients (34.4%), 49 black patients (56.3%), and eight patients of other ethnicities (9.2%). Anastomoses were demonstrated in 41 patients (47.1%). Seventy patients (80.5%) completed the long-term follow-up, of whom 35 had an anastomosis (85.4% of the 41 patients with anastomoses) and 35 did not (76.1% of the 46 patients without anastomoses). Mean leiomyoma volume reduction was 49.1% (P =.018), and reduction of uterine volume was 36.0% (P <.001). Mean clinical follow-up duration was 45 months. Overall, 18 of 70 patients (25.7%) underwent repeat interventions, including 13 (37.1%) with anastomoses and five (14.3%) without anastomoses (P =.029). One patient (1.4%) developed natural amenorrheic change in the long term after UAE. Nineteen patients (27.1%) attempted pregnancy after UAE, and 12 patients had 15 pregnancies, with six pregnancies to full term. CONCLUSIONS: UAE in young patients achieves significant dominant leiomyoma volume reduction and symptomatic improvements, with overall repeat intervention rates of 25.7% in the long term. Uteroovarian artastomoses in young patients are associated with higher rates of repeat intervention after UAE.