Evaluation of atrial function has received less attention than that of the ventricle although normal atrial function is required for optimal overall cardiac function. Obesity is associated with increased cardiovascular morbidity and mortality. In this study, we compared left atrial functions in obese adults (body mass index = BMI >or=30 kg/m(2)) with those in non-obese adults (BMI <30 kg/m(2)) by color tissue Doppler parameters. There were 37 adults with BMI >or=30 kg/m(2) (mean age 36 +/- 11 years) and 26 adults with BMI <30 kg/m(2) (mean age 35 +/- 5 years). Mean BMI was 38 +/- 6 kg/m(2) in the obese group whereas that was 24 +/- 2 kg/m(2) in the non-obese group. For color tissue Doppler imaging, sample volumes were placed on the mid left atrium at the septum, lateral, inferior, and anterior walls. The peak systolic strain (S(s)), peak systolic strain rate (SR(s)), peak early diastolic SR (SR(e)), peak late diastolic SR (SR(a)), peak systolic tissue velocity (TV(s)), peak early diastolic TV (TV(e)) and peak late diastolic TV (TV(a)) values were measured. For each measurement, values in three consecutive cardiac cycles were measured and then averaged. To simplify the analysis, the values at each wall were combined and averaged to obtain mean values. All left atrial systolic function parameters (S(s), SR(s), TV(s)) were similar between the groups. In addition, there was no statistically significant difference at left atrial diastolic function parameters (SR(e), SR(a), TV(e), TV(a)). We could not find any significant difference between obese and non-obese adults at left atrial functions assessed by color tissue Doppler parameters.