Increased hemodynamic load in obese individuals leads to alterations in cardiac geometry and function, including the left atrium (LA). Left atrial ejection force (LAEF) is the force required for late diastolic filling of the left ventricle and has been shown to be associated with age, hypertension, glucose level and weight. Our aim in this study was to investigate the relationship between obesity and LAEF in middle-aged-adult individuals. For this prospective study, a total of 104 individuals, 52 healthy normal weight (BMI < 25) and 52 healthy obese (BMI>30), who were admitted to the cardiology clinic with cardiac complaints were enrolled. Detailed physical examination, anthropometric measurements, glucose levels, lipid levels, interventricular septal thickness (IVSD), left ventricular end-diastolic diameter (LVEDD) on echocardiography, left ventricular posterior wall thickness (LVPWD), left ventricular mass index (LVMI), left ventricular ejection fraction (LVEF), left atrial diameter (LAD), left atrial volume index (LAVI) and left atrial ejection force (LAEF) were calculated. Univariate and multivariate analyses were performed to determine the factors affecting LAEF. Age, male ratio, smoking rate, arterial blood pressure and lipid parameters were similar in both groups. BMI value of the normal weight group was 23.7±1.2 and 38.9±3.7 in the overweight group (p<0.001). The obese group had higher IVSD, LVEED, PWD, LVMI, LAD, LAVI and LAEF compared to the normal weight group (p<0.001 for all values). Pearson correlation analysis showed a significant and moderate correlation between BMI and LAEF (r = 0.582, p<0.001). Regression analysis also showed that BMI was a significant and independent predictor factor for LEAF (p<0.001). Higher BMI is associated with increased LAEF in middle-aged-adult healthy obese individuals.