Aims and Objectives: To identify and analyse the most common hematological disorders diagnosed by doing bone marrow aspiration in a particular group of patients. Material and Method: Bone marrow aspiration was done from Manubrium of the Sternum after injecting 2% xylocaine to the part. Bone marrow smears were prepared and stained with Leishman stain along with the simultaneous staining of the peripheral smears. A complete hemogram including Hb%, PCV, Red cell indices, platelet count, total leucocyte count and differential leucocyte count was also done by Automated cell counter. Finally, the bone marrow and peripheral smears were examined manually under oil immersion. Conclusion: In this study it was found that the most frequently diagnosed hematological disorders on bone marrow aspiration are Megaloblastic and Dimorphic anemias followed by Acute Myeloid and Acute Lymphoblastic Leukemias. Hematological disorders are more common in early adulthood. commonest leukemia in adults and children is Acute Myeloid Leukemia, AML and Acute Lymphoblastic Leukemia, ALL respectively with overall prevalence of leukemias being more in adults.