Background: The epidemiology of hematological diseases in India is largely unknown due to paucity of data. Our centre caters to a major chunk of hematological patients in Eastern India and is one of the largest centers in terms of patient attendance. Objective: The objective of this study was to analyze the OPD data to decipher the hematological disease spectrum in Eastern India. Methods: Hospital data of hematology OPD from July 2015 to June, 2018 was retrived from the hospital information management system. The number of new and follow-up (old) patients attending the OPD were analyzed to know the disease pattern in terms of various benign and malignant hematological disease was assessed. Results: The total number of OPD consultations for the three years was 78809, of which 21851 (27.7%) were new cases and 56958(72.3%) were follow-up (old) visits. Disease characterization could be done for 15517 (71.01%) patients; out of these, 73.3% (11377/15517) were benign and 26.7% (4140/15517) were malignant hematological diseases. Common reasons for consultation in hematology OPD were anemia 9170 cases (59.1%), leukemia 2544 (16.4%), bleeding disorder 1908 (12.3%), lymphoma 946 (6.1%) and myeloma 450(2.9%). Among the benign diseases, most common diagnosis was nutritional deficiency anemia 4403 (38.7%) followed by hemoglobinopathy 3868 (34%), immune thrombocytopenia 944 (8.3%), aplastic anemia 694 (6.1%), hemophilia 637 (5.6%), eosinophilia 148 (1.3%) and thrombosis 80 (0.7%). Among the malignant cases, common causes were leukemia 2351 (56.8%), lymphoma 940 (22.7%) and myeloma 451 (10.9%). Conclusion: Anemia remains the most common reason for OPD consultation even in a tertiary care hematology centre. The major burden of malignant hematological disease is leukemia.