Multiple myeloma is a monoclonal malignant proliferation of plasma cells in the bone marrow that causes osteolytic lesions affecting several bones. Frequently affected sites include the vertebrae, ribs, pelvis, skull, jaw. Usually the patient presents with bone pain, recurrent infections, renal failure and nervous system dysfunction. Jaw lesions, though not uncommon, rarely present as the first sign in multiple myeloma. We are reporting about a clinical case of a 66 year-old female patient who presented with painless swelling of the mandible that has evolved over the previous two months. Clinical manifestations in the jaw like gingival hemorrhage, odontalgia, paresthesias, tooth mobility were not included. In the radiographic examination, an extensive osteolytic lesion, with cortical bone destruction was observed in the left lower jaw. In this case, typical "punched out” lesion was found and enhanced doubt on malignant process. As a routine protocol, an incisional biopsy of lesion was planned but sufficient diagnostic material couldn’t be obtained because of bleeding and fine needle aspiration of tumorous masses confirmed the diagnosis of multiple myeloma (because the microscopic appearance of multiple myeloma is highly characteristic). Additional diagnostic techniques used, such as laboratorial tests (blood tests, serum electrophoresis, urine analysis-Bence Jones proteins) and established the diagnosis of multiple myeloma. To make early diagnosis and start with adequate treatment osteolitic lesion of the jaw is to suspect of multiple myeloma regardless of the rare incidence of this disease.