We encountered a case of endometrial cancer with a poorly differentiated epithelial component, accompanied by a compact proliferation of atypical spindle cells and osteoclast-like giant cells. Immunohistochemically, the epithelial component was EMA and prekeratin positive with vimentin-positive spindle cells, whereas the osteoclast-like giant cells were strongly immunoreactive for CD68. The description of osteoclast-like giant cells adds to the knowledge of endometrial carcinosarcoma tumor biology.