Background and Purpose: Men of age 40 years and above are at risk of  non-cancerous enlargement of the prostate gland also known as benign prostatic hyperplasia (BPH). Adverse drug reactions and treatment relapse limit the effectiveness of orthodox pharmacotherapies. This study evaluated the effect of Cassia fistula hydroalcoholic extract on BPH. Methods: BPH was induced in Wistar rats by subcutaneous injection of 10 mg/kg/day of testosterone propionate (TP) for 7 days. The rats were randomly allotted to five groups: corn oil only; finasteride (FS) 5 mg/kg/day; and C. fistula extract at doses of 100, 200, and 400 mg/kg/day. A sixth group in which BPH was not induced received only the vehicle. At the end of 28 consecutive days of treatment, prostate and testicular weights and indices were evaluated. The in vitro antioxidant capacity of the extract was evaluated using the DPPH free radical scavenging method. Results: The extract showed a very strong free radical scavenging activity with IC50 value of 1.58 µg/mL (IC50 of gallic acid = 0.63 µg/mL) due to the presence of secondary metabolites. The results also showed significant (P?0.0001) reduction in the prostate weight, prostatic index, testes weight, and testes index of C. fistula extract-treated rats when compared with the untreated BPH group. Conclusion: These results suggest that C. fistula extract possesses potentials as a remedy for the treatment of BPH.