Three cases of fibroadenoma associated with carcinoma are reported. These cases were diagnosed within a screening programme as a result of suspicious mammographic findings, and the diagnosis of malignancy was confirmed preoperatively by core biopsy in all cases. The mammographic findings suggestive of carcinoma within fibroadenoma were irregularity of margins in one case and associated new suspicious pleomorphic and linear calcifications in the two other cases. The preoperative diagnosis of carcinoma within fibroadenoma was provided by ultrasound-guided core biopsy in two cases and core biopsy under stereotactic guidance in one case. Whereas asymptomatic fibroadenoma with benign imaging appearances usually does not require further investigation, fibroadenoma with atypical imaging features requires a triple test investigation.