Background. Re-resection for incidental gallbladder cancer (iGBC) is associated with improved survival but little is known about residual disease (RD) and prognostic factors. In this study, survival after re-resection, RD, and prognostic factors are analyzed. Methods. Patients with iGBC were identified from the Netherlands Cancer Registry, and pathology reports of reresected patients were reviewed. Survival and prognostic factors were analyzed. Results. Overall, 463 patients were included; 24% (n = 110) underwent re-resection after a median interval of 66 days. RD was present in 35% of patients and was most frequently found in the lymph nodes (23%). R0 resection was achieved in 93 patients (92%). Median overall survival (OS) of patients without re-resection was 13.7 (95% confidence interval [CI] 11.6-15.6), compared with 52.6 months (95% CI 36.3-68.8) in re-resected patients (p \ 0.001). After re-resection, median OS was superior in patients without RD versus patients with RD (not reached vs. 23.1 months; p \ 0.001). In patients who underwent reresection, RD in the liver (hazard ratio [HR] 5.54; p \ 0.001) and lymph nodes (HR 2.35; p = 0.005) were the only significant prognostic factors in multivariable Electronic supplementary material The online version of this article (