OBJECTIVE:: To conduct a systematic review and metaanalysis of studies evaluating the regression rate of endometrial hyperplasia with oral progestogens and levonorgestrel-releasing intrauterine system. STUDY DESIGN:: Searches were conducted on Medline, Embase, Cochrane Library, and Web of Science, and reference lists of relevant articles were examined. The methodologic index for nonrandomized studies was used for quality assessment. Metaanalysis was performed with random effects model. RESULTS:: There were 24 observational studies (1001 women), of low methodologic quality, evaluating the outcome of regression of endometrial hyperplasia with oral progestogens or levonorgestrel-releasing intrauterine system. Metaanalysis showed that oral progestogens achieved a lower pooled regression rate compared with levonorgestrel-releasing intrauterine system for complex (pooled rate, 66% vs 92%; P <.01) and atypical hyperplasia (pooled rate, 69% vs 90%; P = .03). There was no statistical difference in simple hyperplasia (pooled rate, 89% vs 96%; P = .41). CONCLUSION:: Oral progestogens appear to induce a lower disease regression rate than Levonorgestrel-releasing intrauterine system in the treatment of endometrial hyperplasia.