Synovial hemangiomas are rare benign tumors of vascular origin. A 23-year-old boy presented with knee pain and swelling. The boy had developed symptoms 18-months earlier. He was diagnosed with synovial hemangioma based on magnetic resonnance imaging examination and histopathologic findings of the arthroscopic biopsy tissue. We present the magnetic resonance imaging and histopathologic findings of synovial hemangioma of the knee.