PLASMACYTOMA is an abnormal proliferation of monoclonal B-cells, and it can occur in several forms including multiple myeloma, solitary PLASMACYTOMA of the bone, and extramedullary PLASMACYTOMA primary. The solitary PLASMACYTOMA of the bone accounts for about 3-10% of all plasma cell neoplasms, and occurs most often in the vertebrae, whereas the solitary PLASMACYTOMA of the mandible is an extremely rare occurrence. This case report presents a 61-year-old woman with various underlying diseases diagnosed with solitary PLASMACYTOMA of the mandible. This case is very well documented with radiographic imagery, clinical, and histopathological findings.