Metachronous or synchronous breast carcinoma following or co-existing with colorectal carcinoma are well recognised clinicopathological entities, and the risk of developing both possibly underlines the similarities in carcinogenesis pathways for these carcinomas. We present a 60-year-old housewife with a history of a treated primary colon carcinoma (Duke's C) 15 years previously. Six months ago, during the follow-up care a small sub-areolar lesion was determined in a mammogram. A lumpectomy was performed under local anaesthesia, which revealed an infiltrating ductal carcinoma (6 mm in greatest diameter). Immuno-histochemical assays for oestrogen and progesterone receptors and c-erb B2 ongoprotein were performed. Axillary lymphadenectomy showed 1/11 positive node. She received adjuvant radiotherapy and hormone manipulation. To date, seven months later she is disease free. The aim of this report is to emphasise the risk of metachronous second malignancy of breast or colorectal carcinoma following colorectal carcinomas. A second primary colonic malignancy following breast primary carcinoma is more frequent than inverse clinical form.