Transfusions of autologous blood--the patient's own blood--do not transmit infections and have no immunological consequences. Autologous transfusion includes intraoperative or postoperative salvage of blood losses, as well as transfusion of blood collected immediately before (acute normovolaemic haemodilution) or weeks before surgery in a predonation programme. Salvaged blood can be a good substitute for red cells. Small volume blood salvage can be achieved with simple devices, such as an anticoagulant liner in a rigid canister connected to a wall vacuum line. Filtration is mandatory. For larger volumes of haemorrhage, automated systems operating by semi-continuous flow techniques are yielding standardised washed red blood cell concentrates decreasing the frequency of coagulopathies. It is generally agreed that salvage of blood potentially infected or containing neoplastic cells is contraindicated. In preoperative autologous transfusion programmes, the decision to collect the patient's blood is shared by the anaesthetist and the transfusionist. Anaemia and the possibility of bacteraemia are contraindications. With the present red cell preservative solutions, up to 5 autologous units can be collected in the weeks preceding surgery and stored at 4 degrees C. After the third weekly collection, erythropoiesis stimulation is such that provided the iron intake in adequate collected red cells can be reconstituted within less than a week. Preoperative and intraoperative autologous transfusions are complementary. In the often irreplaceable homologous transfusion as well as in its autologous alternative, medical cooperation and rigorous indications concur in a global blood conservation programme.