Intra-abdominal panniculitis is a tumour-like inflammatory condition of adipose tissue. The aetiology and pathogenesis of the disease is unknown, but a number of associated diseases have been recorded. It has been customary to deal with only primary cases in the literature. This study was undertaken in order to describe the entire spectrum of the disease including primary as well as secondary cases. Eleven patients are reported, nine of which had an associated colorectal disease in direct continuity with areas of intra-abdominal panniculitis. It is concluded that intra-abdominal panniculitis should not be regarded as a specific nosological entity but merely a result of injury to the fat cells. Intra-abdominal panniculitis is seen more often as a secondary local phenomenon than as a primary condition, and in both cases it is associated with considerable differential diagnostic problems. Primary diseases involved are, among others, colorectal carcinoma and diverticulosis. The aetiologic agent(s) are still unknown, but substances liberated from a damaged bowel might play a pathogenetic role.