1397 consecutive suicides were committed in Finland in 1987. 60 (4.3%) of these involved cancer patients, 25 of whom were in remission, 18 in the terminal phase and 17 at other stages of their illness. The background of every case was explored by a structured interview of health care personnel and intimate associates and by examining medical and other case records. The factors connected with and motives for suicide were compared in the two patient groups, the terminally ill and the patients who committed suicide during remission. These groups differed markedly, with the latter having more histories of personal and family mental disorders and suicides among family members. Information which might help clinicians identify suicidal cancer patients was obtained. Withdrawal from social contacts, depression, professed suicidal thoughts and a history of suicide attempt are classical portents of suicide also in cancer patients and should not be ignored. The health care system needs to pay greater heed to the psychological needs of cancer patients. Continuity of the doctor-patient relationship should be guaranteed. Effective symptom control of the terminal patients is very important and could have been achieved in many cases through more competent treatment. Only in a very small minority of cancer patients does suicide seem rational and inevitable.