Purpose: Hypochloremia is a predictor for short-term mortality in patients with cardiovascular disease, but its association with coronary artery disease (CAD) is still unclear. We aimed to assess the impact of hypochloremia on all-cause mortality (short-and long-term) among patients with CAD. Patients and Methods: Based on the registry at Guangdong Provincial People's Hospital in China, we analyzed data of 49,025 hospitalized patients who underwent coronary angiography (CAG) and were diagnosed with CAD from January 2007 to December 2018. To assess the association between hypochloremia and the study endpoints, a logistic-regression model (for 30-day all-cause mortality) and a Cox regression model (for long-term all-cause mortality) were fitted. Results: Overall, 4.4% of the study population showed hypochloremia (<98 mmol/L). During a median follow-up of 5.2 (3.1-7.8) years, a total of 6486 (13.2%) patients died. Patients with hypochloremia were generally older and at risk for diabetes, cardiorenal dysfunction, and morbidity than those without hypochloremia. After adjustment for confounders, hypochloremia remained a significant predictor of mortality risk (30-day all-cause death: adjusted odds ratio [aOR], 1.99; 95% confidence interval, 1.08-3.18; P=0.017 and long-term all-cause death: adjusted hazard ratio [aHR], 1.32; 95% confidence interval, 1.19- 1.47; P<0.001). Conclusion: Hypochloremia is mildly common in patients with CAD and is associated with increased short-and long-term mortality. Meanwhile, it is necessary to further investigate effective and preventive measures and the potential mechanisms of hypochloremia in patients with CAD.