Osteosarcoma is a primary malignant neoplasm of the bone. Osteosarcoma of the jaws especially those of maxilla is rare. The diagnosis of osteosarcomas is difficult and challenging. In this case report we highlight a rare case of osteosarcoma of the maxilla in a 29 year old male patient which was highly aggressive and was initially diagnosed as rhabdomyosarcoma. This case highlights the difficulty in diagnosing osteosarcoma merely from incisional biopsy specimens which may not be representative of the whole tumour. Limited clinical information at incisional biopsy also adds to the difficulty in arriving at the definitive diagnosis. We further discuss the treatment modalities followed in this case.