The disclosure of information to cancer patients is one of the most important issues in oncological practice. In Japan, as in some other countries, few cancer patients were ever given a truthful statement of their diagnosis. However, today more and more patients are being informed of their diagnosis and prognosis. This study investigates the nature of these changes in disclosure policy and suggests possible explanations. We reviewed the medical and nursing charts of 122 adult cancer patients admitted to our hospital in 1993 and 137 admitted in 1998. We examined the information they had been given, and their sociodemographic and medical characteristics. The diagnosis of cancer was shared with 27% of patients in 1993. In 1998, however, 71% were informed of their cancer, and 10% were also told they had a poor prognosis. The rate of disclosure was lower for older patients and those with advanced cancer in both 1993 and 1998. In 1998 the rate was higher in patients undergoing chemotherapy and/or surgery. The higher level of disclosure in 1998 was due basically to the growing importance of informed consent. Psychiatric referrals increased from 2% in 1993 to 10% in 1998. Psychiatrists may have contributed to these changes in the disclosure of information.