Background: Athletes with coronary artery disease (CAD) and diabetes mellitus (DM) are particularly susceptible to severe arrhythmias, which can significantly impair their physical performance and psychological well-being. Identifying and managing risk factors for arrhythmias in this population is crucial for maintaining their health and athletic longevity. Objective: To investigate the risk factors for severe arrhythmia among athletes with CAD and DM, focusing on the association with lipid metabolism disorders. Methods: This study involved 120 athletes hospitalized with CAD complicated by diabetes from August 2020 to August 2022. Participants were divided based on the presence of arrhythmias as detected by dynamic electrocardiograms into an arrhythmia group (n=41) and a non-arrhythmia group (n=79). We analyzed general demographic data, glucose metabolism indices, and lipid profiles, and conducted univariate and multivariate analyses to explore the relationships between these variables and the occurrence of arrhythmias. Results: Of the participants, 34.17% experienced arrhythmias, primarily atrial extrasystoles and sinus tachycardia. Significant risk factors for arrhythmias included older age, a longer duration of diabetes, higher systolic blood pressure, and poor glycemic control as indicated by higher levels of fasting insulin, glycosylated hemoglobin (HbA1c), and the insulin resistance index (HOMA-IR). Lipid metabolism also played a role, with arrhythmic athletes displaying higher levels of high-density lipoprotein cholesterol (HDL-C). Logistic regression showed that age, duration of DM, systolic blood pressure, HbA1c, HOMA-IR, and HDL-C levels were significant predictors of arrhythmias. Conclusion: Athletes with CAD and DM exhibit a heightened risk of severe arrhythmias influenced by multiple factors including glycemic and lipid control. Proactive management of these parameters is essential to minimize arrhythmic risks and support the health and performance of athletes with chronic conditions. Enhanced understanding and intervention strategies are vital for clinicians working with this unique population to ensure optimal outcomes both on and off the field.