The abdominal manifestations of posttransplantation lymphoproliferative disorder show wide variability with potential involvement of all organ systems. The radiologist should be aware of this entity when evaluating patients who have undergone transplantation; both clinical and radiologic findings can mimic other disease processes. Suggestive lesions should prompt a search for additional areas of involvement. In our experience, although sonography can reveal posttransplantation lymphoproliferative disorder of the abdominal viscera, CT more adequately depicts the full extent of disease involvement. Distinguishing between monomorphic and polymorphic subtypes, though important for treatment planning, is not possible by imaging characteristics alone. Therefore, tissue diagnosis is warranted.