Rheumatic heart disease (RHD) is an autoimmune sequel of rheumatic fever (RF) that results in permanent damage to the mitral valves of the heart. Endothelial cells (ECs) of the mitral valves, take up exosomes in the biological fluids which may change the cellular characteristics of the cells. Exosomal miRNAs, have been known to play an imminent role in various diseases. The composition of exosomal miRNAs, varies, under different physiological and pathological conditions. Herein, an attempt has been made to unfurl the role of exosomal miRNA, miR-24-2 in mitral valves damage during RHD. The present study is focused on in-vitro set up and patient samples analysis in which the exosomes were isolated from patient samples (serum and pericardial fluid) of RHD patients and simultaneously from the media extracted RHD patients’ serum stimulated HUVECs (RHD- in-vitro model). Next, HUVECs were, treated with exosomes (component of serum) from RHD patient's serum (R-exo) and normal individuals' serum (N-exo) in-order to evaluate whether HUVECs treated with exosomes brings about morphological changes in HUVECs and change in biological properties. Further, miRNA profiling and RT-PCR of the isolated exosomal RNA revealed that miR-24-2 level was attenuated in RHD patients' samples as well as in the media. Finally, to check cause and effect of the study, functional inhibition of exosomal miR-24-2 was performed, in exosomes treated HUVECs. Decreased expression levels of miR-24-2 as well as endothelial marker (VE cadherin) and increased levels of mesenchymal (SMA-α) and fibrosis marker (TGF-β) was observed in R-exo-treated HUVECs in comparison to N-exo treated HUVECs, which was correlated with altered proteins levels of these markers in the mitral valves of RHD patients. Thus, these findings suggests, decreased exosomal miR-24-2 levels may lead to enhanced TGF-β production and mitral valves dysfunction (stenosis and regurgitation) during RHD