Musculoskeletal sonography has an important role in the evaluation of the postoperative orthopedic patient. One major advantage of sonography over magnetic resonance imaging and computed tomography is that artifact from metal, which is common after orthopedic surgery, is relatively limited. This allows a clear assessment of the soft tissues for abnormalities such as tendon tear, tenosynovitis, joint effusion, and soft tissue infection. Sonography also has a role in evaluation of recurrent soft tissue tumor, bone healing, and limb amputation. This article first discusses the basic technical aspects of musculoskeletal sonography and is followed by sonographic examples of normal anatomy. Common applications of musculoskeletal sonography in evaluation of the postoperative orthopedic patient are reviewed, including sonography after tendon surgery, assessment of soft tissues adjacent to orthopedic hardware, recurrent musculoskeletal soft tissue tumors, sonography of bone healing, and evaluation of limb amputation. Guidelines and pitfalls of these applications are reviewed.