Background: Left ventricular end-diastolic diameter (LVEDD) is a common parameter in echocardiography. Increased LVEDD is associated with left ventricular (LV) dysfunction. However, the association between LVEDD and all-cause mortality in patients with coronary artery disease (CAD) is uncertain. Methods: This study enrolled 33,147 patients with CAD who had undergone transthoracic echocardiography between January 2007 and December 2018 from the Cardiorenal Improvement study (NCT04407936). The patients were stratified into four groups based on the quartile of LVEDD (Quartile 1: LVEDD <43 mm, Quartile 2: 43 mm < LVEDD <46 mm, Quartile 3: 46 mm < LVEDD <51 mm, Quartile 4: LVEDD >51 mm) and were categorized into two groups (Quartile 1-3 versus Quartile 4). Survival curves were generated with the Kaplan-Meier analysis, and the differences between groups were assessed by log-rank test. Restricted cubic splines and cox proportional hazards models were used to investigate the association with LVEDD and all-cause mortality. Results: A total of 33,147 patients (average age: 63.0 +/- 10.6 years; 24.0% female) were included in the final analysis. In the average follow-up period of 5.2 years, a total of 4288 patients died. The mortality of the larger LVEDD group (Quartile 4) was significantly higher than the lower LVEDD groups (Quartile 1-3) (18.05% vs 11.15%, p < 0.001). After adjusting for confounding factors, patients with the larger LVEDD (Quartile 4) had a 1.19-fold risk for all-cause mortality (95% CI: 1.09-1.30) compared with the lower quartile (Quartile 1-3). Conclusions: Enlarged LVEDD is an independent predictor of all-cause mortality in patients with CAD. LVEDD measurements may be helpful for risk stratification and providing therapeutic targets for the management of CAD patients.