Mastalgia has been classified as an aberration of the normal, rather than a disease. We present an age-matched, case-control study which compares the reproductive factors of patients with severe cyclical and noncyclical mastalgia with control groups of women who presented to a breast clinic but in whom no clinical abnormality was found and who did not later develop breast disease. There were few statistically significant differences in reproductive factors between the cases and controls, which lends some support to the concept that mastalgia can be considered to be an aberration of the normal.