Doppler echocardiography provides the ability to measure blood flow velocities noinvasively. These blood flow velocities can be used to obtain powerful hemodynamic information about systolic contractility of the left ventricle, which in the past could only be determined from invasive cardiac catheterization or cumbersome pulse recordings. Volumetric flow rates can be measured using the hydraulic principle of flow through a rigid tube, providing a measurement of stroke volume and cardiac output. The rate of the left ventricular pressure rise derived from a mitral regurgitation velocity curve provides a nonejection phase index of systolic contractility. Acceleration time can be obtained from an ascending aortic velocity and is an indicator of maximum myocardial force. Systolic time intervals can now be quickly and accurately obtained from the standard Doppler tracings. These quantitative measurements of the status of the left ventricular are accurate, reproducible, and should be incorporated into the routine noninvasive assessment of patients with cardiac disease.