BACKGROUND: Studies comparing left atrial (LA) function after surgical closure or percutaneous closure in patients with an atrial septal defect (ASD) are lacking. METHODS: Between 1 and 3 years after ASD treatment, we retrospectively analyzed the medical records and transthoracic echocardiographic images of patients who had been diagnosed with an ASD after 20 years of age and who had undergone surgical closure (ASD-S) or percutaneous device closure (ASD-D). We measured LA peak systolic, early diastolic, and late diastolic strain values using 2-dimensional (2D) speckle tracking echocardiography (STE) and calculated reservoir, conduit, and contraction strain. RESULTS: The reservoir strain value of the ASD-D groups was 25.2% ± 7.4%, which was lower compared to the control group (33.6% ± 5.5%) (p = 0.004). The LA conduit strain and the LA contraction values of the ASD-D group were also lower compared to the control group (−13.8% ± 5.8% vs. −20.4% ± 4.7%, p = 0.034; −11.3% ± 4.2% vs. −13.2% ± 2.5%, p = 0.037, respectively). The reservoir, conduit, and contraction strains of the ASD-S group were 27.8% ± 8.8%, −15.3% ± 6.4%, and −12.5% ± 5.8%, respectively, and were not different from those of the control group or the ASD-D group. CONCLUSIONS: The 2D STE is a suitable method for evaluating LA function after ASD closure. Our results demonstrate that 1 year after device closure, the LA reservoir, conduit and contraction function were reduced in ASD-D group compared to healthy controls, while there was no difference between the ASD-S and ASD-D groups.