In Tokushima Prefecture, Japan, 41,922 women (26,669 in actual number) were subjected to mass screening with physical examination from 1970-1977. In 42 including 10 of so-called "interval cancer", breast cancer was detected. Those with breast cancer detected by mass screening were in the earlier stage of the disease as compared to those diagnosed through regular medical care at our-patient clinic during the same period. Procedures such as inspection and palpation are readily carried out and early occurrences of breast cancer can be detected.