Vitreous hemorrhage is common, with varied clinical manifestations and causes. The most common causes include proliferative diabetic retinopathy, vitreous detachment with or without retinal breaks, and trauma. Less common causes include vascular occlusive disease, retinal arterial macroaneurysm, hemoglobinopathies, age-related macular degeneration, intraocular tumors, and others. The natural history depends on the underlying cause, and is generally more favorable in eyes without underlying disease. Treatment is directed at the underlying cause, such as laser photo-coagulation for proliferative diabetic retinopathy or for retinal breaks. Occasionally, hemorrhage does not resolve spontaneously and vitrectomy surgery is necessary and beneficial. New strategies for the treatment of vitreous hemorrhage, such as pharmacologic vitreous liquefaction, may be important in the future.