Background: The arterial switch operation (ASO) is the preferred surgical treatment for transposition of the great arteries with intact ventricular septum (TGA/IVS). Delays beyond the first month of life may lead to left ventricular deconditioning. This study evaluated the perioperative outcomes of the neonatal ASO within the first month versus later in life in a middle-income country where late presentations are common, aiming to assess the safety of the ASO beyond early intervention. Method: This retrospective study included 295 TGA/IVS patients who underwent the ASO from January 2010 to December 2023. We excluded those with other significant cardiac anomalies or deconditioned left ventricle (LV). Preoperatively, we evaluated the left ventricular ejection fraction and the posterior LV wall thickness to ascertain the adequacy of the LV. Study outcomes included in-hospital mortality, postoperative chest reexploration, extracorporeal membrane oxygenation use, and the duration of ventilation and hospitalization. Results: One hundred and fifty of 295 patients (51%) had the ASO within 30 days of life (early group) whereas 145 patients (49%) had the ASO beyond 30 days of life (late group). The mean age was 20.3 ± 5.7 days for the early group and 80.0 ± 60.0 days for the late group (P < .001). The late group had significantly lower in-hospital mortality (4.8% vs 14.0%, P = .007) and a lower incidence of chest reexploration (8.3% vs 17.3%, P = .020), with odds ratio of 0.312 and 0.430, respectively. Conclusion: Our findings indicate that the ASO performed after 30 days of life for those with a preserved LV is associated with satisfactory perioperative outcomes, underscoring the importance of carefully selecting patients who present late for the ASO.