Physicians' attitudes towards the disclosure of a cancer diagnosis to 114 consecutive patients (age range, 65-93 years; median 78 years) admitted to the Tokyo Metropolitan Tama Geriatric Hospital from April 1994 to May 1995 were analyzed utilizing a questionnaire administered to the attending physicians. Eighty-seven patients (76%) had been informed of their diagnosis before the initiation of cancer treatment, while 27 patients (24%) were not told. 'To carry out the treatment under patient's understanding' and 'consideration for patient's quality of life' were the major reasons for diagnosis disclosure, while 'lack of patient's ability to understand the information' and 'family's wish that the patient not be informed of the truth' were the major reasons for non-disclosure. Dementia, deteriorated performance status, and non-curability were major factors related to non-disclosure. Even with decisional ability, 15% of patients were not told their cancer diagnosis because wishes of their families were preferred. The current results suggest that telling cancer diagnosis to the elderly patients will not yield negative attitude of the patients and that there is no rationale for physicians to hesitate to disclose cancer diagnosis merely because of patient's high age.