Eighteen patients with 20 primary lesions of small intestinal lymphoma of the 'Western' type were examined to determine the double-contrast radiographic features of the disease with pathological correlation. The radiographic appearances on double-contrast study were divided into five groups: polypoid (3 lesions), stricturing (6), non-stricturing (3), aneurysmal (3), and intussusception (5). In the first four groups, ulceration, signs of submucosal tumour, and displacement of adjacent loops were frequent. Two early lesions confined to the submucosal layer were also seen. There was a close association between the radiographic appearance and macroscopic findings of the resected specimens, including the cross section of the tumour, but no correlation with the cell type. These results indicate that the double-contrast study accurately reflects the morphological changes of primary small intestinal lymphoma.