A laparotomy performed for an occlusive syndrome, disclosed the presence of an ileal lymphoma in a renal graft recipient, 17 years after a first renal transplant. Mesenteric lymph node and spleen involvement were associated. The morphology of the large cells, the type of infiltration of the lymph node simulating metastatic carcinoma or malignant histiocytosis were highly suggestive of a new type of high grade malignancy lymphoma recently described which is called 'large cell anaplastic ML'. The immunolabelling study confirmed this diagnosis, demonstrating the following phenotype CD4, CD25 (TAC), CD30 (Ki-1), OKT 9 (transferrin receptor), EMA and HLA DR positivity. The tumour cells were negative for the other T, B and histiomonocytic markers. This case, of a large cell anaplastic Ki-1 positive lymphoma, expressing CD4, in a renal graft recipient shows that high grade ML in such patients are not all of the B cell type.