Experience with benign breast disorders has been analyzed in 3 nonwestern populations: Hong Kong, India, and Northern Nigeria. Similarities to and differences from Western experience are found, but of great interest are notable differences between these populations which, as yet, lack explanation. All show "fibroadenosis" and fibroadenoma as common conditions, but the frequency with which phyllodes tumor is diagnosed varies between different centers in India as well as between different racial groups. Tuberculosis is another interesting example--wide differences in the frequency of breast infection are found although tuberculosis itself is common in all 3 countries. The value of prospective studies was shown when mastalgia was studied in this way in India. Often considered a "Western" affliction, these authors have been able to study 112 cases of mastalgia and found it to be twice as common as cancer as a presentation. These differing experiences between populations have been little explored and must hold promise for unravelling some of the enigmas of benign breast disorders in all countries.