Malignant tumors of the breast with stromal multinucleated giant cells are rare entity of uncertain clinical significance. There have been few reports on the fine needle aspiration cytologic(FNAC) findings about these rare tumors. We report a FNAC case of invasive mammary carcinoma with osteoclast-like giant cells not only for its rare occurrence but in particular for its distinctive cytologic picture on aspirated material. The patient was a 40-year-old woman who presented with a right breast mass for one month. Mammography showed a well-demarcated rounded mass density without calcification. The aspirates of FNAC were highly cellular and two main cell types were seen; malignant epithelial cells and osteoclast-like multinucleated giant cells. The carcinoma cells occurred singly or arranged in loose clusters with ill-defined cytoplasm, oval nuclei, coarse chromatin and small but distinct nucleoli. The multinucleated giant cells showed variable number of nuclei with prominent nucleoli and abundant dense oxyphilic cytoplasm. The immunocytochemical studies suggested that osteoclast-like giant cells were not of epithelial origin, but rather of histlocytic origin.