This report concerns two patients with severe protein losing enteropathy and refractory diarrhea due to AA amyloidosis who were successfully treated with corticosteroid and octreotide. In these patients, biopsied tissues from the gastrointestinal (GI) tract showed extensive deposition of AA amyloid, which was caused by rheumatoid arthritis in one case and was of unidentified etiology in the other. Both patients manifested severe diarrhea unresponsive to conventional treatment with hypoproteinemia, and protein leakage from the small intestine to the ascending colon was confirmed by 99mTc-diethylene triamine pentaacetic acid human serum albumin (HSA-D) scintigraphy. Soon after starting a long-acting somatostatin analogue, octreotide, with co-administration of oral prednisolone, their general status improved in parallel with a rapid decrease in the volume of watery diarrhea and an increase in serum levels of albumin and IgG. Also on 99mTc-HSA-D scintigraphy protein leakage from the GI tract was apparently decreased in both patients. Combination therapy with a somatostatin analogue and corticosteroid may be effective for protein losing enteropathy with intractable diarrhea ascribable to GI amyloidosis. Because of the lack of specific therapies in this serious clinical situation, the described therapy should actively be considered as a therapeutic option not only in AA amyloidosis, but also in other types of systemic amyloidosis.