Introduction: Atrial septal defect is one of the congenital heart diseases. An atrial septal defect (ASD) represents a communication between the left and right atrium leading to left to right shunt. It makes up about 10% of all congenital heart diseases after delivery and up to 30—40% of heart defects diagnosed in patients aged over 40 years. Objectives: To identify the status of cardiac remodeling after surgical patch closure of adult congenital atrial septal defects. Methodology: The descriptive and observation study was carried out atDepartment of Cardiac Surgery, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from January 2013 to April 2015. The patients both male and female undergoing surgical closure of atrial septal defect, Department of Cardiac Surgery, BSMMU, Dhaka, Bangladesh. Total sixty (60) patients were studied, thirty (30) in each group. Group A: Thirty (30) patients of surgical closure of ASD at or before age of 25 years. Group B: Thirty (30) patients of surgical closure of ASD at or after age of 25 years. A purposive sampling technique was used for sample selection. The sample size was determined by using the standard formula for comparison between two proportions. To make it more convenient and reduce the error sample size of this study was fixed at 60 (30 in each group). Careful history regarding the complaints of Exerttional dyspnoea, Palpitation, Fatigability, General weakness, Electrocardiography (ECG), Chest X ray, Echocardiography (Echo), Left atrial diameter (LA), -Left ventricular internal diameter at the end of diaslole (LVIDd), -Left ventricular internal diameter at the end of systole (LVIDs), Interventricular septal thickness (IVST), Posterior wall thickness (PWT), Fractional shortening (FS), Ejection fraction (EF) were measured. Results: From the result it was found that exertional dyspnoea in 60.0%, palpitation in 70.0%, fatigue in 66.6% and general weakness in 53.33% in group A and in group B exertional dyspnoea in 80.0%, palpitation in 73.33%, fatigability in 63.33% and general weakness in 80.0%. There was no significant difference in presenting complaints distribution in between two groups. From the ECG findings between two study groups it was found that arrhythmia in 13.33%, left axis deviation in 10.0%, right axis deviation 23.330% and in group B arrhythmia in 16.67%, left axis deviation in 13.33%, right axis deviation 36.67%. There were differences between two groups regarding ECG findings. In early age group there was few complains but complains are more in late age group. From the types of ASD between two study groups it was revealed that septum secundum defect is 66.67%, Septum primum 20 % and sinous venosus defect in 13.33 % in group A. In group B septum secundum defect is 76.67%, Septum primum 13.33 % and sinous venosus defect in 10 %. There was no significant difference in type of ASD in between two groups. Conclusion: This study concluded that cardiac remodeling occurs after surgical closure of atrial septal defect in all age group and degree of cardiac remodeling was better in early age group (up to 25 years) compared with late age group (>25 years).