The cause-specific mortality of women with cancer of the breast or of the intestines (= small intestine and colon) diagnosed in 1953-70 in Finland was analyzed with respect to the extent of the disease, the age of the patient at the time of diagnosis, and the follow-up time. The total mortality in breast-cancer patients was higher than had been expected during the entire follow-up period (maximum of 18 years), whereas in patients with intestinal cancer no more than slight excess mortality existed after 5 years of follow-up. The mortality from cardiovascular diseases was less than had been expected among patients with intestinal cancer. Patients with non-localized cancer of the breast had a risk of dying from accidents and other violent causes of death during the first 5 years of follow-up which was slightly higher than expected. From information compiled from various sources, the Finnish Cancer Registry records not only the official cause of death mentioned on the death certificate, but also a "corrected" cause of death. With this correction, the mortality from forms of malignancy other than the primary cancer was lower than had been expected during the first 5 years of follow-up, and subsequently reached the level expected. In regard to specific sites, mortality lower than that expected was observed for cancer of the stomach (both breast- and intestinal-cancer patients), and cancer of the cervix uteri (breast-cancer patients). In patients with localized breast cancer, the mortality from leukaemia was higher than that expected after 5 years of follow-up. No mutual excess risk was demonstrable with breast and intestinal cancers.