Aims: We aimed to evaluate whether leptin and ghrelin responses to cardiopulmonary bypass (CPB) are dependent on type 2 diabetes and whether these responses are associated with interleukin-6 (IL-6), high-sensitivity C-reactive protein (hsCRP), cortisol and insulin. Methods: We examined stress-response patterns in plasma leptin, ghrelin, hsCRP, IL-6, cortisol and insulin levels before and up to 5 days after cardiopulmonary bypass in 20 patients with type 2 diabetes and 20 patients without diabetes. Results: Plasma leptin levels increased significantly in both groups (p< 0.05) and rose significantly higher in diabetics when compared with nondiabetic patients (p=. 0.004). Plasma ghrelin levels increased significantly only in diabetics (p=. 0.033). Patients with and without diabetes showed significantly elevated serum concentrations of IL-6, hsCRP, cortisol and insulin (p< 0.005 for IL-6, hsCRP; p< 0.05 for cortisol, insulin) but the difference between the two groups was nonsignificant.Leptin was independently predicted by hsCRP (p< 0.05, F=. 2.9), gender (women p< 0.001, F=. 4.7), body mass index (BMI p< 0.0001, F=. 6.1) whereas ghrelin levels were not associated with any variables in the total patient population. (critical F=. 2.26, p≤ 0.05). Conclusions: Acute phase response in diabetics differs by higher leptin levels independent of BMI, gender and IL-6, hsCRP, insulin and cortisol levels. © 2012 Elsevier Ireland Ltd.