Purpose: To evaluate transarterial chemoembolization (TACE) use prior to and concomitantly with sorafenib in patients with unresectable hepatocellular carcinoma (HCC) across different global regions. Materials and Methods: GIDEON is an observational registry study of more than 3000 HCC patients. Patients with histologically, cytologically, or radiographically diagnosed HCC, and for whom a decision had been made to treat with sorafenib, were eligible. Patients were enrolled into the registry from 39 countries beginning in January 2009, with the last patient follow-up in April 2012. Detailed data on treatment history, treatment patterns, adverse events, and outcomes were collected. All treatment decisions were at the discretion of the treating physicians. Documented approval from local ethics committees was obtained, and all patients provided signed informed consent. Descriptive statistics, including minimum, median, and maximum, were calculated for metric data, and frequency tables for categorical data. Kaplan-Meier estimates with 95% confidence intervals were calculated for survival end points. Results: A total of 3202 patients were eligible for safety analysis, of whom 2631 (82.2%) were male. Median age was 62 years (range, 15-98 years). A total of 1511 (47.2%) patients underwent TACE prior to sorafenib; 325 (10.1%) underwent TACE concomitantly. TACE prior to sorafenib was more common in Japan and Asia- Pacific compared with all other regions (362 [71.3%] and 560 [60.3%] vs 12-209 [13.3%-37.1%]). Adverse events were reported in 2732 (85.3%) patients overall, with no notable differences in the incidence of adverse events, regardless of TACE treatment history. Overall survival was 12.7 months in prior-TACE patients, 9.2 months in non-prior-TACE patients, 21.6 months in concomitant-TACE patients, and 9.7 months in non-concomitant-TACE patients. Conclusion: Global variation exists in TACE use in sorafenib-treated HCC patients. The combination of TACE with sorafenib appears to be a well-tolerated and viable therapeutic approach. (C) RSNA, 2016