OBJECTIVE: Poor vagally mediated heart rate variability (vmHRV) is a mechanism linking depression to coronary heart disease (CHD). Reduced vmHRV is also considered an index of emotion dysregulation-the frequent use of maladaptive emotion regulation strategies, one of the most important being expressive suppression-which is a key component of depression. Therefore, this study aimed to investigate the moderating role of expressive suppression in the relation between depression and vmHRV in patients with CHD. METHODS: The sample included 235 patients with CHD (mean [standard deviation] age = 61.6 [9.8] years; 12% women) admitted to cardiac rehabilitation after a cardiac intervention. The Beck Depression Inventory-II was administered to assess depressive symptoms. Emotion regulation strategies based on either expressive suppression or cognitive reappraisal were assessed through the Emotion Regulation Questionnaire. Resting electrocardiographic recordings were collected for 5 minutes to compute HRV indices. RESULTS: Expressive suppression moderated the relation between depressive symptoms and vmHRV ( b = -0.03, p = .012). Patients with lower expressive suppression scores showed no association between depressive symptoms and vmHRV ( b = -0.00, p = .94), whereas those with higher expressive suppression scores showed a significant negative association between depressive symptoms and vmHRV ( b = -0.05, p = .015). CONCLUSIONS: The use of expressive suppression is likely to potentiate the relation between depressive symptoms and poor vmHRV, which could increase the cardiac risk in these patients. Targeting emotion regulation skills in cardiac rehabilitation programs may be useful for reducing the impact of depression in cardiac patients.