Left atrial (LA) function assessment is important in clinical practice. We studied peak atrial tissue velocity (A') and quantitative echocardiographic methods of LA function in 120 patients (54 men; mean age 58 years) who were in sinus rhythm. Patients were divided into 2 groups: patients with increased left ventricular mass; and healthy subjects. There was no difference for peak late filling velocity (A) and A velocity time integral between groups. Patients with increased left ventricular mass had higher A', LA ejection fraction, LA ejection force, and LA kinetic energy. A' correlated well with LA ejection fraction (r = 0.8), LA ejection force (r = 0.87), and LA kinetic energy (r = 0.87). A' could also assess LA function for patients with depressed left ventricular function. Subsequently, we assessed A' in 16 patients with restrictive physiology and found that A' also correlated well with quantitative methods of LA function. A' correlates well with quantitative methods of LA function, and could be readily applied for quantifying LA contribution to diastolic performance in clinical practice.