OBJECTIVE: Uterine fibroids are common benign tumors that cause symptoms like bleeding and pain, with mifepristone showing potential for treatment. This study examines the impact of mifepristone dosage on fibroid size and clinical outcomes to inform future research and treatment. METHODS: A comprehensive search of databases including PubMed, Scopus, and Cochrane Library was conducted up to September 2024. Only randomized controlled trials (RCTs) studies were included, with data analyzed using a random-effects model. Subgroup analyses were performed based on dosage and treatment duration. RESULTS: Sixteen RCTs were included in the analysis. The random-effects model showed that mifepristone, compared to placebo, resulted in a non-significant reduction in leiomyoma volume (SMD = -1.11, 95 % CI:2.63 to 0.40, P = 0.15). A daily dose of 25 mg mifepristone significantly reduced leiomyoma volume compared to 10 mg (SMD = -0.54, 95 % CI:1.06 to -0.02, P = 0.04). Extended use of 10 mg/day versus 5 mg/day also showed a non-significant reduction in leiomyoma volume (SMD = -0.05, 95 % CI:0.23 to 0.12, P = 0.56). CONCLUSION: Mifepristone did not demonstrate a significant advantage over placebo in reducing uterine fibroid volume. While higher doses (25 mg daily) showed a statistically significant reduction compared to lower doses (10 mg daily), the overall clinical significance remains unclear. Further research is needed to clarify the optimal use of mifepristone in treating uterine fibroids.