Lipid rich carcinoma is a rare subtype recently separated from the usual types of breast carcinoma by its morphologic characteristics and rather poor prognosis than the letters. We have experienced a case of lipid rich carcinoma in a 46 year old woman who had a slowly growing palpable mass in her right breast without nipple retraction. Grossly, the tumor was 3cm in diameter and poorly demarcated. The cut surfaces were uniformly firm but not as hard, and grayish white colored. Microscopically, the mass consisted of sheens and strands of malignant cells, having infiltrative borders throughout a fibrous matrix. The tumor cells were large and had faintly eosinophilic cytoplasms which were somewhat bubbly or vacuolated. The nuclei were fairly regular, although in some areas thor were pleomorphic and hyperchromatic. Large amount of lipid wag demonstrated within the cytoplasm by oil red-O stain applied to frozen sections. It is interest that both the peripheral portion of the breast mass and the metastatic lesion of the axillary node contained areas of typical infiltrating ductal cell carcinoma.