A 2012 systematic review and meta-analysis of randomized controlled trials on emergency department-initiated tobacco control (ETC) showed only short-term efficacy. The aim of this study was to update data through May 2015.After registering the study protocol on the international prospective register of systematic reviews (PROSPERO) in May 2015, we searched 7 databases and the gray literature. Our outcome of interest was the point prevalence of tobacco-use abstinence at 1-month, 3-month, 6-month, or 12-month follow-up. We calculated the relative risk (RR) of tobacco-use abstinence after ETC at each follow-up time separately for each study and then pooled Mantel-Haenszel RRs by follow-up time. These results were pooled with results of the 7 studies included in the previous review. We calculated the effect of ETC on the combined point prevalence of tobacco-use abstinence across all follow-up times by using generalized linear mixed models.We retrieved 4 additional studies, one published as an abstract, comprising 1,392 participants overall. The 1-month follow-up point prevalence of tobacco-use abstinence after ETC resulted in an RR of 1.49 (95% confidence interval [CI], 1.08-2.05) across 3 studies; 3-month follow-up, an RR of 1.38 (95% CI, 1.12-1.71) across 9 studies; 6-month follow-up, an RR of 1.09 (95% CI, 0.84-1.41) across 6 studies; and 12-month follow-up, an RR of 1.26 (95% CI, 1.00-1.59) across 3 studies. The effect on the combined point prevalence of abstinence was an RR of 1.40 (95% CI, 1.06-1.86) (P = .02).ETC is effective in promoting continual tobacco-use abstinence up to 12 months after intervention. ETC may be a critically important public health strategy for engaging hard-to-reach smokers in tobacco-use cessation.