Polypoid lesions of the gallbladder taken from 103 patients were examined to correlate clinical indicators with pathological characteristics. By ultrasonographic examination, no carcinoma was found in polypoid lesions with a diameter less than 1 cm. However, the incidence of carcinoma in those with diameters greater than 1 cm was 23%, a lower rate than expected from previous pathological studies. Comparison of ultrasonographic and actual measurements suggested that the size of cholesterol polyps tended to be overestimated by ultrasonography, suggesting that the apparent risk of cancer was decreased by cholesterol polyps. Laparoscopic cholecystectomy was performed in 30 patients with polyps. No complications were encountered, and operative time was significantly shorter (p < 0.01) than in the 116 laparoscopic cholecystectomies for cholelithiasis. This study demonstrated the difficulty in distinguishing large benign polyps from carcinoma by ultrasonography. To complete the diagnosis with less invasive intervention, we propose the use of laparoscopic cholecystectomy for patients with polypoid lesions larger than 1 cm by ultrasonographic estimation.