The clinico‐pathological aspects of 19 cases of cystosarcoma phyllodes (CP) were reviewed with special attention to the occurrence of associated breast carcinoma (BC). Twelve women had histologically benign, 4 had borderline and 3 malignant CP. Recurrent CP was diagnosed in 9 women within 1 to 15 years after initial treatment. Of the 19 women, 5 had associated in situ or invasive BC, 2 with the primary CP and 3 with its recurrences. In 1 case the BC was located within the confines of the CP, whereas in 4 women the CP and BC were separate lesions. The frequency of incidentally found BC in this group of women with CP does not support the hypothesis of an increased risk of BC development in women with CP.