Multiple myeloma, the most common bone malignancy, is occurring with increasing frequency in older persons. Typical symptoms are bone pain, malaise, anemia, renal insufficiency, and hypercalcemia. Incidental discovery on comprehensive laboratory panels is common. The disease is diagnosed with serum or urine protein electrophoresis or immunofixation and bone marrow aspirate analysis. Skeletal radiographs are important in staging multiple myeloma and revealing lytic lesions, vertebral compression fractures, and osteoporosis. Magnetic resonance imaging and positron emission tomography or computed tomography are emerging as useful tools in the evaluation of patients with myeloma; magnetic resonance imaging is preferred for evaluating acute spinal compression. Nuclear bone scans and dual energy x-ray absorptiometry have no role in the diagnosis and staging of myeloma. The differential diagnosis of monoclonal gammopathies includes monoclonal gammopathy of uncertain significance, smoldering (asymptomatic) and symptomatic multiple myeloma, amyloidosis, B-cell non-Hodgkin lymphoma, Waldenström macroglobulinemia, and rare plasma cell leukemia and heavy chain diseases. Patients with monoclonal gammopathy of uncertain significance or smoldering multiple myeloma should be followed closely, but not treated. Symptomatic multiple myeloma is treated with chemotherapy followed by autologous stem cell transplantation, if possible. Melphalan, prednisolone, dexamethasone, vincristine, doxorubicin, bortezomib, and thalidomide and its analogue lenalidomide have been used successfully. It is important that family physicians recognize and appropriately treat multiple myeloma complications. Bone pain is treated with opiates, bisphosphonates, radiotherapy, vertebroplasty, or kyphoplasty; nephrotoxic nonsteroidal anti-inflammatory drugs should be avoided. Hypercalcemia is treated with isotonic saline infusions, steroids, furosemide, or bisphosphonates. Because of susceptibility to infections, patients require broad-spectrum antibiotics for febrile illness and immunization against influenza, pneumococcus, and Haemophilus influenzae B. Five-year survival rates approach 33 percent, and the median survival rate is 33 months.