Technique and sites for marrow aspiration has been discussed. This examination is of essential diagnostic value in some of the blood disorders such as leukaemias and anemias. Bone marrow culture is useful for isolating microorganism in cases of septicaemias. Chromosomal analysis of bone marrow cells is done to detect congenital malformations. Administering drugs or fluids and transfusion of blood can be done through bone marrow cavity when peripheral vascular failure and extensive skin burns occur. It is not advisable to perform it in coagulation disorders of blood like haemophilia. Fracture of tibia has resulted very rarely and death from cardiac temponade has also been reported.