The ever-increasing demand for blood and blood products has resulted in extensive and accelerated research in the area of blood replacement. Improvements have been made in techniques for prolonging the shelf life of blood. Autotransfusion, a concept originating the early 1800s, has been refined and advanced to a point where it is a safe and efficacious method of supplying blood for patients needing emergency or elective procedures. In addition, oxygen-carrying artificial blood substitutes, specifically perfluorocarbons and stroma-free hemoglobin, are currently under investigation. The area of blood replacement holds many exciting prospects both now and for the future.