Two very rare cases of a lipid-secreting carcinoma of the breast are reported, and a review of the pertinent literature. The patients were both women, aged 70 and 81, respectively. Both of their clinical stagings were T2aN1aM0, stage II., and radical mastectomies were performed. On examination of the resected specimens, the tumors did not differ from the general findings of breast cancer. Microscopically, H-E stain showed the tumor cells to have a foamy and vacuolated eosinophilic cytoplasm. Lipid stain and an electron microscopic study were performed and showed that the tumor cells contained large amounts of neutral lipid droplets in their cytoplasm.