Left atrium enlargement is a pathophysiological response to volume and pressure overload associated with a wide range of cardiovascular disorders leading to left ventricle systolic and diastolic dysfunction. Physiological factors contribute to significant differences in left atrium size in normal individuals. Moreover, left atrium enlargement was shown to have a significant prognostic value for cardiovascular events such as heart failure, atrial fibrillation or stroke, and increased cardiovascular and all-cause mortality rates. Current imaging techniques such as two- and three dimensional echocardiography, cardiac magnetic resonance imaging and multi-detector computed tomography allow a detailed assessment of the left atrium. The current paper aims to offer an overview of two-dimensional echocardiography parameters which provide data concerning left atrium dimensions and phasic functions and may lead to a better understanding of left atrium physiology and pathology.