The mammograms of 17 women with pathologically proved breast hamartomas were reviewed. Abnormal masses were detected on 12. Nine women had masses with benign features. Two of these had findings considered classic for hamartoma. In three cases, the appearance of the mass was suggestive of carcinoma. The breasts were very dense in four of five women without detectable mass. The findings suggest that the classic mammographic appearance of breast hamartomas is less common than previously reported, which may be explained by earlier detection of small hamartomas.