Background A major technical challenge of prostatic arterial embolization (PAE) is the identification and catheterization of the prostatic arteries (PAs). Recently, MR angiography has been shown to help visualize PAs, but the clinical utility of MR angiography for this purpose is not known. Purpose To determine the efficacy of contrast material-enhanced MR angiography in identifying the PA and to evaluate its role in PAE for benign prostatic hyperplasia (BPH). Materials and Methods In this prospective study, 100 consecutive men who were scheduled to undergo PAE for BPH from January 2015 to May 2017 were assigned by using a randomized block design to either group A (n = 50; mean age, 71.7 years ± 11.9 [standard deviation]) without MR angiography or group B (n = 50; mean age, 72.3 years ± 12.2) with MR angiography prior to PAE. MR angiography findings of the PA anatomy were compared with those of digital subtraction angiography (DSA). The Student t test and Wilcoxon rank-sum test were used to compare the differences between the parameters indicating the performance of PAE. Results The mean age of the 100 men in the study was 72.0 years ± 11.8 (range, 51-88 years). Compared with DSA as the reference standard, MR angiography identified PAs with a sensitivity of 91.5% (97 of 106) and a positive predictive value of 100% (97 of 97). With the knowledge of tube obliquity and anatomy, group B had lower procedure times than group A (82.3 minutes ± 5.4 vs 123.9 minutes ± 12.4, P < .001) and shorter fluoroscopy times (13.8 minutes ± 2.7 vs 28.5 minutes ± 8.0, P < .001). Additionally, radiation dose was reduced for group A versus group B, from a median of 920 to 339 mGy (P = .004). Conclusion Contrast-enhanced MR angiography can accurately show anatomy for the prostate arteries, leading to shorter prostatic artery embolization times and lower radiation dose than when preprocedural prostate MR angiography is not performed. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Prince in this issue.