This document provides updated guidelines and reference values for cardiac chamber quantification by echocardiography. It summarizes recommendations for measuring and evaluating left ventricular size, function, mass and regional wall motion. Reference values are given for linear dimensions, volumes and ejection fraction of the left ventricle based on a large number of normal subjects. The document also summarizes guidelines for assessing right ventricular size and function, as well as the size and function of the left and right atria, aortic root dimensions, and inferior vena cava size. Partition values are only provided for left ventricular ejection fraction and left atrial volume due to limitations of existing data.