PURPOSE: To study the factors that might impact infarction of individual uterine leiomyomas and total tumor burden after uterine artery embolization (UAE). MATERIALS AND METHODS: This retrospective study included 91 patients (mean age, 44 y [range, 34-54 y]) who underwent UAE with tris-acryl gelatin microspheres (TAGMs) or nonspherical polyvinyl alcohol (PVA) particles. Twenty-one patients were treated with PVA (23%) and 70 were treated with TAGMs (77%). A total of 356 uterine leiomyomas were assessed, with a median uterine volume of 533 cm3 (range, 321-848 cm3). A reader masked to demographic and technical details reviewed contrast-enhanced magnetic resonance images before and 3 months after UAE to estimate the extent of tumor infarction. RESULTS: There was no significant difference in global or individual tumor infarction rate between embolizations with TAGMs and PVA particles (P = .73 and P = .3, respectively). Global infarction was not affected by age (P = .53), race (P = .12), number of leiomyomas (P = .72), or uterine volume (P = .74). Leiomyoma size did not influence individual tumor infarction (P = .41). Leiomyoma location was the sole factor that influenced individual tumor infarction rates, with pedunculated serosal tumors significantly less likely to show complete infarction than transmural tumors (odds ratio, 0.24; P = .01). CONCLUSIONS: Nonspherical PVA particles and TAGMs produce similar rates of uterine leiomyoma infarction. Complete infarction of individual tumors is less likely in serosal and pedunculated serosal tumors.