Objective: The aim of the study was to analyze the impact of rupture size on surgical outcomes of ventricular septal rupture. Methods: During a 15-year period, from Jan 2006 to Dec 2020, 112 patients underwent repairs of postinfarction ventricular septal rupture. Data were collected on clinical, angiographic, and echocardiographic findings; operative procedures; early morbidity and mortality; and survival time. Univariable and multivariable analyses were performed to identify risk factors of 30-day mortality. Results: Thirty-day mortality was 7.1% for the whole cohort. The mean survival time estimate was 147.2 (95% Cl 135.6-158.9) months, with a 3-year survival rate of 91.2% and a 5-year survival rate of 89.0%. Multivariable analysis regarded rupture enlargement gradient as an independent risk factor of 30-day mortality. The ROC curve indicated that rupture enlargement gradient predicted 30-day mortality with high accuracy. Conclusions: Delayed surgery could be considered for patients who respond well to aggressive treatment. Rupture enlargement gradient is an independent risk factor for postoperative 30-days morality of delayed VSR repair and has good predictive power for the prognosis of VSR patients.