AIM: To explore the relationship of embolic particle size used in prostate artery embolisation (PAE) to patient outcomes. MATERIALS AND METHODS: A systematic review of PubMed, EMBASE, and the Cochrane database was undertaken to identify all existing studies using PAE for benign prostatic hyperplasia (BPH). Inclusion criteria included prospective studies reporting baseline and 12-month International Prostate Symptom Score (IPSS) and particle size. Exclusion criteria were overlapping studies, commentaries, abstracts, and letters. Data extraction from eligible studies included the size of embolic particle, particle material, and baseline and 12-month values for the following patient outcomes: IPSS, IPSS quality of life, urinary flow rate (Q-max), prostate volume, prostate specific antigen, and post-void residual volume. A meta-regression analysis was then undertaken to examine the relationship of particle size to patient outcome measures. RESULTS: Six studies with a total of 687 patients were identified. Meta-regression analysis demonstrated particle size as a statistically significant (p<0.001) moderator of 12-month IPSS change following PAE. No statistically significant relationships were identified with other patient outcome measures. CONCLUSION: Smaller embolic particle size is associated with a greater reduction in IPSS following PAE.