FVIII inhibitor development in haemophilia A (HA) patients, especially those with severe manifestations is a serious adverse effect in patients with haemophilia A, and the clinical management of these patients is very difficult as most don't respond to conventional treatment. Many genetic and non-genetic risk factors have been proposed however, these are diverse in different population groups, highlighting the importance of determining specific risk factors for each population. F8 mutations and especially inversions, which are the most common causative mutation in severe HA, have been significantly associated with inhibitor development earlier, however there is no conclusive data so far with regard to Indian haemophiliacs. This study provides novel evidence that intron 22 inversions in the F8 gene are indeed significantly associated with FVIII inhibitor development in Indian haemophiliacs. Further studies with other risk factors would enable better insights into the immune response towards FVIII in these patients, and possibly help to characterize patients at a higher risk for inhibitor development.