Background: Gallbladder cancer (GBC) is a rare malignancy characterized by high invasiveness and poor survival. In a nation-wide cancer survey, the age-standardized incidence rate of GBC was the highest in Jeju Island compared to 15 other provinces in Korea. The purpose of this study was to compare the clinical outcomes of GBC according to the nature of diagnosis, that is, incidental versus non-incidental. Materials and Methods: Consecutive patients who were newly diagnosed with GBC at the Digestive Disease Center and Department of Internal Medicine, Cheju Halla General Hospital, between November 2008 and November 2011, were enrolled and divided into 2 groups: incidental gallbladder cancer (IGBC) and non-incidental gallbladder cancer (NIGBC). Clinical outcomes were retrospectively compared between the two groups. Results: Seventy-nine patients were enrolled and analyzed in our study. Thirty-three (41.8%) and 46 (58.2%) were identified as IGBC and NIGBC, respectively. The proportions of patients with gallstone disease, gallbladder polyp, and cholecystectomy were significantly different between the two groups. Additionally, the median survival rate was significantly higher for patients with IGBC than for those with NIGBC (11.4, 95% confidence interval, 5.6-13.7 vs 4.0, 95% confidence interval 3.03-5.96 months; p=0.01) during a median follow-up period of 5.7 months. Conclusions: Patients with IGBC showed better clinical prognosis than those with NIGBC. Therefore, patients with gallstone disease or gallbladder polyps, major predictive risk factors for IGBC, should undergo advanced work-up for chelecystectomy.