Background/Aims: To evaluate the efficacy and safety ofadalimumab (ADA) in moderately to severely active ulcerativecolitis (UC) patients who are unresponsive to traditional therapy. Methods: Electronic databases, including the PubMed, Embase, and Cochrane databases, were searched to April 20, 2014. UC-related randomized controlled trials (RCTs) that compared ADA with placebo were eligible. Review Manager 5.1 was used for data analysis. Results: This meta-analysis included three RCTs. ADA was considerably more effective compared with a placebo, and it increased the ratio of patients with clinical remission, clinical responses, mucosal healing and inflammatory bowel disease questionnaire responses in the induction and maintenance phases (p<0.05), as well as patients with steroid-free remission (p<0.05) during the maintenance phase. Clinical remission was achieved in a greater number of UC cases in the ADA 160/80/40 mg groups (0/2/4 week, every other week) compared with the placebo group at week 8 (p=0.006) and week 52 (p=0.0002), whereas the week 8 clinical remission rate was equivalent between the ADA 80/40 mg groups and the placebo group. Among the patients who received immunomodulators (IMM) at baseline, ADA was superior to the placebo in terms of inducing clinical remission (p=0.01). Between-group differences were not observed in terms of serious adverse events (p=0.61). Conclusions: ADA, particularly at doses of 160/80/40 mg (0/2/4 week, every other week), is effective and safe in patients with moderate-to-severe UC who are unresponsive to traditional treatment. Concomitant IMM therapy may improve the short-term therapeutic efficacy of ADA. (Gut Liver 2016;10:262-274)