We aimed to analyse the echocardiographical characteristics of healthy subjects and determine the causal mechanism of the development of physiological mitral regurgitation (PMR). A total of 130 healthy subjects were divided into two groups according to whether or not PMR was detected. There were no statistical differences between the two groups in terms of the mean values of the systolic and diastolic left ventricular internal diameters and the left atrial diameter. The mean values of the length and thickness of the anterior mitral valve (AMV) and the mitral annular diameter (MAD) from subjects in group 1 (with PMR) were statistically different from those of group 2 (without PMR). In conclusion, the AMV was slightly longer and thicker and the MAD was smaller in subjects with PMR than in subjects without PMR. The changes observed in the AMV and the mitral annulus may play a causal role in the development of PMR.