Plasmacytoma of the jaw bones and oral cavity, as in other anatomic sites, comprises three distinct entities: multiple myeloma, solitary plasmacytoma of bone, and extramedullary plasmacytoma. This article is a retrospective study of 13 cases; 9 occurred in the mandible and 4 in the maxilla. The most common radiographic finding was a radiolucency that many times was superimposed on the roots or apices of nearby teeth. The most common symptom was localized pain, and the most frequent clinical sign was a raised red lesion on the alveolar ridge. The disease affects older persons, and the posterior mandible is the most frequently reported location. The degree of dysplasia of tumor cells was evaluated as there is a reported correlation with survival rates.