A case of tumefactive liver infiltration in primary amyloidosis is presented. Both liver radionucleotide scanning and selective liver angiography indicated a local mass (8 X 15 cm) in the right liver lobe, but at laparotomy no liver tumour was found. The liver was enlarged. It was pale and firmer than usual. Liver biopsy specimens showed that about 30% of the liver mass was formed of amyloid deposited mainly between the liver cells in the perisinusoidal space. Adjacent lymph nodes were histologically normal. Amyloid was later found in a kidney biopsy, but a rectal biopsy showed no amyloid. 1.5 years later the patient is reasonably well, further ruling out the likelihood of neoplastic or malignant liver involvement. Echo studies of the liver showed only generalized enlargement with no focal region, indicating usefulness of this technique in diagnosing liver disease.