This study was designed to compare baseline data and clinical outcome between patients with prostate enlargement/benign prostatic hyperplasia (PE/BPH) who underwent unilateral and bilateral prostatic arterial embolization (PAE) for the relief of lower urinary tract symptoms (LUTS). This single-center, ambispective cohort study compared 122 consecutive patients (mean age 66.7 years) with unilateral versus bilateral PAE from March 2009 to December 2011. Selective PAE was performed with 100- and 200-mu m nonspherical polyvinyl alcohol (PVA) particles by a unilateral femoral approach. Bilateral PAE was performed in 103 (84.4 \%) patients (group A). The remaining 19 (15.6 \%) patients underwent unilateral PAE (group B). Mean follow-up time was 6.7 months in group A and 7.3 months in group B. Mean prostate volume, PSA, International prostate symptom score/quality of life (IPSS/QoL) and post-void residual volume (PVR) reduction, and peak flow rate (Qmax) improvement were 19.4 mL, 1.68 ng/mL, 11.8/2.0 points, 32.9 mL, and 3.9 mL/s in group A and 11.5 mL, 1.98 ng/mL, 8.9/1.4 points, 53.8 mL, and 4.58 mL/s in group B. Poor clinical outcome was observed in 24.3 \% of patients from group A and 47.4 \% from group B (p = 0.04). PAE is a safe and effective technique that can induce 48 \% improvement in the IPSS score and a prostate volume reduction of 19 \%, with good clinical outcome in up to 75 \% of treated patients. Bilateral PAE seems to lead to better clinical results; however, up to 50 \% of patients after unilateral PAE may have a good clinical outcome.