We describe two cases of adult T-cell leukaemia/lymphoma (ATLL) with oesophageal involvement. The first case, a 51-year-old Japanese woman with an acute subtype of ATLL, had an irregular ulcerative lesion in the distal oesophagus. The second case, a 76-year-old Japanese man with a lymphoma subtype of ATLL, had a polypoid lesion in the middle portion of the oesophagus. Both cases had gastric involvement. Biopsies from these lesions revealed mucosal invasion of ATLL cells in each case. Combination chemotherapy was ineffective in both cases. Prospective and careful examination of additional cases may eventually provide specific advice for treatment of this unusual condition.