Aims: Global Investigation of therapeutic DEcisions in hepatocellular carcinoma and Of its treatment with sorafeNib (GIDEON), a global, non-interventional, surveillance study, aims to evaluate the safety of sorafenib in all patients with unresectable hepatocellular carcinoma (uHCC) under real-life practice conditions, particularly Child-Pugh B patients, who were not well represented in clinical trials. Methods: Treatment decisions are determined by each physician according to local prescribing guidelines and clinical practice. Patients with uHCC who are candidates for systemic therapy, and for whom a decision has been made to treat with sorafenib, are eligible for inclusion. Demographic data and medical and disease history are recorded at entry. Sorafenib dosing and adverse events (AEs) are collected throughout the study. Results: From January 2009 to April 2011, >3000 patients from 39 countries were enrolled. The prespecified first interim analysis was conducted when the initial approximately 500 treated patients had been followed up for ≥4 months; 479 were valid for safety evaluation. Preplanned subgroup analyses indicate differences in patient characteristics, disease aetiology and previous treatments by region. Variation in sorafenib dosing by specialty are also observed; Child-Pugh status did not appear to influence the starting dose of sorafenib. The type and incidence of AEs was consistent with findings from previous clinical studies. AE profiles were comparable between Child-Pugh subgroups. Discussion: The GIDEON study is generating a large, robust database from a broad population of patients with uHCC. First interim analyses have shown global and regional differences in patient characteristics, disease aetiology and practice patterns. Subsequent planned analyses will allow further evaluation of early trends. © 2012 Blackwell Publishing Ltd.