The aim of this paper is to determine the opinion of healthy individuals among whom might be future cancer patients, about communicating the diagnosis of this disease to the patients. An inquiry was performed on a representative sample of the spanish population. It covered 2493 persons over the age of 18. Two questions were asked: 1) "If you suffered from cancer would you prefer your physician to tell you or not?" 2) "If the cancer patient were a very near relative of yours (parent, etc.), would you wish the physician to inform the patient or not?" 69% gave a positive reply to the first question and 23% answered in the negative. The number of affirmative answers was significantly higher among the following groups: men (76%); young persons (82%); individuals with a high cultural level (79%; the unemployed (80%); and non-believers (86%). 42% answered "yes" to the second question and 44% answered "no". The number of affirmative answers was significantly higher among the following: men (48%); young people (54%); non-believers (65%); it was significantly lower among housewives (33%). The conclusion is that the diagnosis of cancer should not be communicated indiscriminately to the patient in all cases. The future problem lies in determining which persons should be informed of the diagnosis.