An efficacy of CT in the preoperative staging diagnosis of gallbladder cancer was evaluated. CT findings were recorded following general rules for surgical and pathological studies on cancer of biliary tract proposed by Japanese society of biliary surgery. Serosal invasion (S factor), direct hepatic invasion (H inf factor), lymph node metastasis (N factor), bile duct invasion (B factor), duodenal invasion (Du factor) and finally preoperative staging diagnosis were included in this study. Conclusion is as follows. 1) False positive results were predominating in S and H inf factor, sensitivity was 76.0% and 50.0% respectively. 2) In B factor, the result was poor, the sensitivity 44.4%. 3) In N factor, CT was effective, the sensitivity 77.6%. 4) Finally it was concluded that CT can play an important role in staging diagnosis of gallbladder cancer, the sensitivity was 93.1%.