We encountered a patient with primary cervical leiomyoma with remarkable calcification and ossification. A 68-year-old man presenting with induration and swelling of the left submandibular region was found to have nodular lesions with calcifications in the left submandibular region and the upper mediastinum on CT. Fine needle aspiration biopsies (FNAB) of the left submandibular lesion revealed no malignancy. Resection was performed for definitive diagnosis and treatment. The resected specimen contained a solid tumor, which was markedly calcified and ossified on the cut surface. Histopathological examination showed proliferating spindle cells in a tangled and crossed arrangement. Immunohistochemically, the spindle cells were stained intensely with α-SMA and h-caldesmon, consistent with smooth muscle cells. These findings led to a definitive diagnosis of leiomyoma with calcification and ossification. This is extremely rare and the preoperative differentiation from other tumors of the head and neck was very difficult. By resection of the submandibular tumor, both definitive diagnosis of leiomyoma by histopathological and immunohistochemical analyses and treatment could be carried out. However, as the tumor in the upper mediastinum was most likely to be leiomyoma with calcification, he did not wish to undergo its biopsy and resection immediately. We have continued the follow-up.