Anesthesiologists are frequently met with patients that are in need for blood transfusion during their anesthetic practice. Blood transfusion though life saving carries the potential for producing many complications e.g. transmission of infectious diseases as AIDS, viral hepatitis and others, non infectious risks of blood transfusion including hemolytic reactions which may lead to acute renal failure and death and non hemolytic reactions as allergic reactions. The aim of this essay is to study and discuss the many factors that allow blood conservation during anesthesia. These include: Minimizing the need for Blood transfusion through induced hypotension, local infiltration with sympathomymetic amines, tourniquets, autologus transfusion and other methods. Blood volume replacement by methods other than blood transfusion like intravenous fluids, component therapy and red cell substitutes is another technique that can be used to avoid the use of blood transfusion and it will be also discussed in this essay.