Para-articular cysts frequently are seen on routine imaging examinations. They may be clinically asymptomatic or may cause pain, swelling, or impaired joint function. They often are associated with underlying joint disorders, such as trauma, degeneration, or inflammation. This article discusses the cause, symptoms, and appearance of para-articular cysts on various imaging examinations including arthrography, ultrasound, CT scan, and MR imaging. Specific attention is focused on those cystic masses appearing around the hip, knee, ankle and foot, shoulder, elbow, wrist and hand, spine, temporomandibular joints, and periosteum.