Cancer in the gallbladder is rare, and each year about 160 cases are registered in Denmark. Most malignant tumours in the gallbladder are adenocarcinomas. We present a rare case of signet ring cell carcinoma of the gallbladder. Signet ring cell carcinomas are particularly aggressive. The tumours are often disseminated at the time of diagnosis, and it may be difficult to determine the primary origin.