Various imaging techniques have been used in the management of multiple myeloma (MM).The current standard is still the radiographic skeletal survey due to its widespread availability, low cost and its ability to assess the whole skeletal system.However, plain films of the skeleton could miss up to 25% of bone lesions in MM.Other modalities such as computerized tomographic (CT) scan and magnetic resonance imaging are more sensitive but are limited by potential renal insufficiency due to intravenous contrast and by only a focal evaluation of the imaged part of the body.Positron emission tomography (PET) especially when fused with CT scan provides not only provide anatomic visualization of the whole body but also provide the functional activities of lesions, both medullary and extramedullary,in MM.In this session, we will discuss the mechanics of FDG-PET scans, define its role in differentiating MGUS vs MM, and in the diagnosis, response assessment and evaluation of relapse/progression in MM.