Introduction: Use of factor VIII and factor IX concentrates has decreased the morbidity and mortality in patients with hemophilia. But with increasing use of factor concentrates, one major complication occurring is formation of inhibitors to Factor VIII and Factor IX which results in poor response to factor administration making control of hemorrhages more difficult. Different studies show enormous difference in inhibitor occurrence. The prevalence of inhibitors is estimated to be between 5 and 10% of all hemophilia A with 20% of severe hemophilia A patients and 3–5% of all hemophilia B patients Aim of study: To study the occurrence of inhibitors in hemophilia A and hemophilia B affected children receiving factor replacement therapy. Material and Methods: The study was conducted in department of pediatrics, S.M.S. medical College, jaipur, India from april 2011 to March 2013 and a total of 100 children with hemophilia were screened for inhibitors to factor VIII and IX with quantification done by Bethesda assay. Results: Out of 100 hemophilia children screened 81(81.00%) had hemophilia A and 19 (19.00%) had hemophilia B. Among 81 Hemophilia A patients, 56 (69.14%) had severe, 13 (16.05%) had moderate and 12 (14.81) had mild hemophilia A disease. Among 19 hemophilia B patients, 15 (78.95%) and 4 (21.05%) had severe and moderate hemophilia B respectively. 4 patients, all belonging to severe hemophilia A, were found to be inhibitor positive. Thus 4.94% (4 out of 81) of total hemophilia A and 7.14% (4 out of 58) of severe hemophilia A patients were found inhibitor positive. None of the 19 hemophilia B patients showed inhibitors. Inhibitor titers ranged from 3.1 BU/mL to 128 BU/mL. Conclusions: Percentage of patients showing inhibitor positivity is slightly lesser than previous studies. Inhibitor occerrance in still low in Indian patients than their western counterparts. However,with increasing use of factor concentrates in hemophiliac children in developing setups, inhibitor occurrence is expected to increase and screening at regular intervals advised , to detect inhibitors early.