Blood levels can be boosted by a direct transfusion, injection of hormones to boost red blood cell production (eg. erythropoietin), reducing the oxygen at altitude or simulated altitude or by gene therapy. The question about who should get a blood boost has developed into serious questions for both medical practitioners and sports administrators. Increased haemovigilance activities in recent years have demonstrated that many previous concepts about the benefit of blood transfusions to restore a normal haemoglobin level in anaemic patients need to be reviewed. Blood transfusions can save lives but it is also true that transfusions can kill. The NBA and NHMRC have recently issued guidelines to define the indications for transfusion in 6 different medical scenarios. However much of the evidence to establish guidelines is weak and we await the results of large prospective studies. The blood boosting effects of erythropoietin administration can result in transfusion independence for many patients with renal failure however it is now realised that a subgroup of patients with malignancies will do worse if given erythropoietin. For endurance athletes, blood boosting can enhance performance however any form of blood boosting is currently illegal for elite athletes. Some argue that athletes who are slightly deficient need or deserve a blood boost. Following the death of many young athletes with extremely elevated haematocrits some 10-20 years ago, sports administrators have instituted testing programs that have at least have limited excessive blood boosting in athletes. The biological passport and tests for erythropoietin and homologous transfusions have all been useful monitors of illegal blood boosting and a series of athletes have been sanctioned.