A multicentre study of 51 cases of lymph-node infarction seen in the 30-year period 1956 to 1985 was conducted in order to assess both the short- and long-term prognostic implications of the condition. In 14 cases malignant lymphoma was found synchronously with the infarct. Of the remaining 37 patients with apparently 'benign' lymph-node infarction only six showed manifestations of malignant lymphoma in the follow-up time studied (mean = 48 months; range 1-156 months). These subsequent malignant lymphomas all occurred within 2 years of the lymph-node infarction. A postal enquiry and collation of other cases in the medical literature indicates that a minority (26 of 81) have developed malignant lymphoma, and that these lymphomas, too, have all appeared within 2 years. Thorough examination of both the infarcted lymph nodes and others resected at the same time is mandatory in order to exclude concomitant or underlying malignant lymphoma. Two years after lymph-node infarction the risk of malignant lymphoma is negligible.