The intent of blood doping is to increase maximal aerobic power by increasing the capacity of blood to carry oxygen. This manipulation gained notoriety in the sports world because of rumors of blood doping by competitors in endurance events. Researchers also have become interested in induced erythrocythemia because its study provides insight into the limiting factor(s) of maximal aerobic power (Vo2max). It is concluded in this review that to increase Vo2max, it is necessary to elevate significantly the hemoglobin concentration by infusing at least 900 ml of blood. The use of inadequate reinfusion volumes, premature reinfusion of the blood following withdrawal, and storage of the blood by refrigeration rather than by freezing are major reasons for the contradictory findings from earlier studies of blood doping. Changes in blood volume and 2,3-diphosphoglycerate following blood doping are transient and, other than during the first 24 h post infusion, appear to be inconsequential. In addition, this review also examines related issues such as attendant hemodynamic and lactate changes, the need of controls, and ethical considerations in blood doping.