Background: Atrial function is an integral part of cardiac function which is often neglected. The presence of coronary artery disease(CAD) may impair atrial function. This study investigated if atrial mechanical dysfunction was present in patients with CAD by tissue Doppler echocardiography(TDI). Methods: Echocardiography with TDI was performed in 118 patients with CAD, and compared with 100 normal controls with comparable age and heart rate. Regional atrial function was assessed at the left(LA) and right(RA) atrial free wall and inter-atrial septum(IAS). The peak regional atrial contraction velocity of(VA) and the timing of mechanical events were compared. Results: The VA in the LA(5.0± 2.6 Vs 7.7± 2.6 cm/s), IAS(4.8± 1.7 Vs 5.7± 1.5 cm/s) and RA(6.8± 3.1 Vs 9.2± 2.9 cm/s) were significantly decreased in patients with CAD when compared with controls(all p< 0.001). Patients with impaired systolic function(ejection fraction ≤ 50% ) had significantly lower VA in the LA and IAS than those with ejection fraction >50% (both p< 0.001); and were lower in those with restrictive filling pattern(RFP) than non-RFP of diastolic dysfunction(both p< 0.05). The VA in all the subgroups was lower than controls. In contrast, transmitral atrial velocity was unable to reveal any abnormality except in the subgroup with a RFP. The LA dimension, area and volume were increased in the disease groups, but were largely unchanged in the RA despite abnormal VA. The physiological inter-atrial delay for the onset and peak atrial contraction between the RA and LA were unaffected by CAD. Conclusions: The atrial contractile function in both atria was impaired in the presence of CAD, especially in the LA. This was detected even in patients with preserved systolic function or mild diastolic dysfunction such as non-RFP. Direct assessment of atrial velocity by TDI may better reflect atrial mechanical function than transmitral atrial velocity. The presence of coronary artery disease (CAD) may impair atrial function. This study investigated if atrial mechanical dysfunction was present in patients with CAD by tissue Doppler echocardiography (TDI) . Methods: Echocardiography with TDI was performed in 118 patients with CAD, and compared with 100 normal controls with comparable age and heart rate. Regional atrial function was assessed at the left (LA) and right (RA) atrial free wall and inter-atrial The peak regional atrial contraction velocity of (VA) and the timing of mechanical events were compared. Results: The VA in the LA (5.0 ± 2.6 Vs 7.7 ± 2.6 cm / s), IAS (4.8 ± 1.7 Vs 5.7 ± 1.5 cm / s) and RA (6.8 ± 3.1 vs 9.2 ± 2.9 cm / s) were significantly decreased in patients with CAD when compared with controls (all p <0.001). Patients with impaired systolic function (ejection fraction ≤ 50% ) had significantly lower VA in the LA and IAS th all those with ejection fraction> 50% (both p <0.001); and were lower in those with restrictive filling pattern (RFP) than non-RFP of diastolic dysfunction (both p <0.05) controls. In contrast, transmitral atrial velocity was unable to reveal any abnormality except in the subgroup with a RFP. The LA dimension, area and volume were increased in the disease groups, but were largely yet in the RA even abnormal VA. The physiological inter atrial delay for the onset and peak atrial contraction between the RA and LA were unaffected by CAD. Conclusions: The atrial contractile function in both atria was impaired in the presence of CAD, especially in the LA. This was detected even in patients with preserved systolic function or mild diastolic dysfunction such as non-RFP. Direct assessment of atrial velocity by TDI may better reflect atrial mechanical function than transmitral atrial velocity.