Background and Objectives: ABO blood group antigens remains the most important antigens in transfusion and transplantation due to immune genecity. Aim of this study was to determine the prevalence of ABO blood group antigens along with the subgroups of A and AB i.e A1, A2, A1B and A2B and Bombay blood group. Material and Methods: This was a cross-sectional study conducted over a period of one year from April 2022 to March 2023. Blood samples were received from blood donors, blood recipients, OPD and IPD patients. The ABO blood groups and subgroup ping were determined by the antigen-antibody agglutination method by the test tube method using commercially prepared monoclonal antisera anti-A, anti-B, anti AB, anti-D, anti-A1 lectin and anti-H for forward grouping. The data was presented in tabulated form. Results:Out of 15527 ABO blood grouping done in the blood centre, 4164(26.8%) were blood group A, 4834 (31.13%) were blood group B, 5059(32.58%) were blood group O and 1470(9.46%) were blood group AB. Out of 4164 A blood groups , frequency of A1 blood group was 94.09% (3917), and A2 was 5.93%(247). Out of total 1470 AB blood groups, A1B was 85.5%(1257) and A2B was 14.48%(213. It was found that A2 in AB blood group was more frequent in occurrence than A2 in A blood group. The blood samples were also typed for anti-H to know the frequency of Bombay blood group. No case of bombay blood group was found during the study period. Conclusion: Though subgroups of A and AB are rare but they can cause severe transfusion reactions which can be life threatening. By conducting this study in an associated hospital Blood Centre, the dangerous blood transfusion reactions occurring due to these subgroups can be avoided.