BACKGROUNDHaematological disorders include a wide range of diseases ranging from anaemias to haematological malignancies. Examination of the marrow is critically important in the study and management of wide variety of haematological disorders. Bone marrow examination is safe and useful test in reaching the final diagnosis. MATERIALS AND METHODSThis descriptive study was carried out in the Postgraduate Department of Pathology, Government Medical College, Jammu, India over a period of five years (November 2011 to October 2016). 1600 cases were diagnosed by bone marrow aspiration. Complete blood count, peripheral smear and bone marrow study were performed in all cases. Those with inconclusive report due to inadequate sample were dropped. RESULTSBone marrow aspiration from 1600 patients were analysed. The male-to-female ratio was 1.3: 1 with maximum number of cases in the age group of 11 -20 years and 40% of the cases were in the paediatric age group. Nutritional anaemia contributed to the most common haematological disorders. Among them, the incidence of megaloblastic anaemia was highest (50%). The other haematological disorders were ITP (5%), Aplastic anaemia (2.50%), Haemolytic anaemia (0.62%), Haemoparasites (0.62%), Hypersplenism (0.37%), Hypereosinophilic syndrome (0.31%), Haemophagocytic syndrome (0.25%), Congenital dyserythropoietic anaemia (0.18%), Thalassemia (0.12%), Sickle cell disease (0.06%) and Niemann's pick disease (0.06%). In Malignant haematological disorders, the most common was found to be leukaemia (15.75%). Amongst these, acute lymphoblastic leukaemia (6.25%) was more common. Others were Multiple myeloma (1.62%), MDS (0.5%), Waldenstrom's macroglobulinaemia (0.25%), lymphomas (0.25%) and CMML (0.12%). One case of myeloproliferative variant of hypereosinophilic syndrome (0.06%) was diagnosed during the study period. Bone marrow mets (0.37%) were observed to be the most important cause of secondary bone marrow involvement by a non-haematological malignancy. CONCLUSIONBone marrow study plays a very important role not only in determining the cause of disease, but also helps in establishing a definitive diagnosis. It is one of the most common and safe procedures done routinely on outpatient basis.