Mitral valve prolapse (MVP) is a common disorder, afflicting 2 % to 3 % of the general population. Despite the general belief of a benign disorder, there is an increasing awareness of an association between mitral valve prolapse and sudden cardiac death from arrhythmia and also atherosclerosis. Monocyte to high density lipoprotein ratio (MHR) is a new tool for predicting inflammation, which plays a major role in atherosclerosis.  To evaluate the relationship between MHR and the presence of MVP.The study population consisted of 82 patients with MVP and the control group of 78 normal individuals. Transthoracic echocardiograpy was performed for all of the study population and peripheral venous blood samples were drawn for measuring MHR and other haemotological parameters.The patients with MVP were more likely to have higher MHR values (15.82±6.01 in MVP patients and 13.30 ± 6.43 in controls; p=0.011). Monocyte counts and MHR of the MVP group were significantly higher than the control group and MHR values were directly proportional with the regurgitation area.The MHR is strongly associated with MVP and regurgitation area and might be a prognostic factor for patients with MVP (Tab. 3, Fig. 1, Ref. 15).