In 31 patients with proven gastric malignancy, computed tomography (CT) was done before surgical exploration. Tumour growth was assessed with each method independently, but following the same protocol. The results of the CT examination were compared with the surgical findings and the diagnostic accuracy of CT was evaluated. Liver metastases could be demonstrated with specificity 10/10 and sensitivity 20/21. The predictive value of the positive test (Pv+) was 10/11, and the predictive value of the negative test (Pv-) was 20/20. Tumour growth to the pancreas was shown by CT with specificity 4/5 and sensitivity 26/26, with Pv+ = 4/4 and Pv- = 26/27. Enlarged lymph nodes around the coeliac axis could be shown with specificity 6/6, Pv+ = 18/18 and Pv- = 6/13. The accuracy of CT was also evaluated regarding tumour growth to oesophagus, colon and greater and lesser omenta. Tumour resectability was predicted by the radiologist with the help of CT. The specificity was 26/26 and sensitivity 4/5, Pv+ = 26/27 and Pv- = 4/4. In this study, therefore, CT had high diagnostic accuracy in regard to extent of intraabdominal growth and resectability. In selected patients it may thus be possible, when resection is not feasible, to avoid exploratory laparotomy.