Cytogenetic analysis of 25 breast fibroadenomas (FA) showed clonal chromosome alterations in three cases. Insertion (12;?) (q15;?) and deletion (2) (q14q31 or q32) were detected as a sole change in cases 1 and 3, respectively. Case 2 displayed the karyotype 45,XX,t(1;8;16)(q25;q23;q22-23), add (7)(p14), rea(15), -17. The present findings are discussed together with the reports on FA in the literature.