IntroductionPlatelet-related disease may result from an abnormal platelet count, namely thrombocytopenia or thrombocythemia, or altered platelet function, and thus is associated with bleeding or with thrombotic manifestation. Thrombocytopenia is defined as a subnormal number of platelets i.e. less than 1,50,000/µL in the peripheral blood. It can lead to inadequate clot formation and increased risk of bleeding and is a common indication for bone marrow aspiration and biopsy. MethodologyThe study was a hospital-based prospective observational study from January 2019 to June 2020. All cases of thrombocytopenia which were diagnosed first on haematology analyser (platelet counts <150,000/µL) and confirmed subsequently by peripheral smear with/without bleeding manifestations due to thrombocytopenia were taken up for the study. The aims and objectives of this study were to find out the epidemiological spectrum and prevalence of thrombocytopenia according to age and sex along with the correlation of haematological and bone marrow findings of such patients. ResultThis study comprised 100 cases of thrombocytopenia, with acute leukaemia accounting for the majority (28/100), followed by dimorphic anaemia (15/100), megaloblastic anaemia (11/100), hypocellular marrow, infection, and other conditions. All cases (100%) displayed the clinical symptom of widespread weakness and pallor, which was followed by fatiguability (72%) and dyspnoea (48%). Many thrombocytopenic individuals also had lymphadenopathy and hepatomegaly, the last two least common appearances. Lymphadenopathy and hepatomegaly which were the last two least common presentations were present in a significant number of thrombocytopenic patients. ConclusionThe study of bone marrow is helpful in the diagnosis of thrombocytopenia cases. Bone marrow examination is a simple, safe outpatient procedure and yields an impressive amount of diagnostically valuable data in a wide variety of disorders of thrombocytopenia. An evaluation of the patient's bone marrow unquestionably aids in the early diagnosis and treatment of their ailment.