Objectives. Type 2 diabetes has been described a risk factor for cardiovascular disease by inducing endothelial dysfunction. The present study investigated whether eNOS-activation may be also dysregulated in cardiac tissue obtained from patients suffering from type 2-diabetes. Methods: We performed immunohistochemical measurements of translocated eNOS-activation as well as eNOS-phosphorylation at Ser1177, Thr495, Ser 635, Ser116 in isolated right atrial trabeculae of patients undergoing cardiac bypass surgery with (n=6, 65.2±5.2 years) and without type 2 diabetes (n=7, 70.5±1.9 years). In addition, we investigated the oxidative and nitrosative stress markers and the influence of pharmacological stimulation of AT1-receptors on the eNOS-phoshorylation at Ser1177. Results: Translocation-dependent eNOS activation was similar in both groups. The same holds true for eNOS-phosphorylation at Ser116. eNOS phosphorylation at Ser635 was significantly increased, whereas eNOS-phosphorylation of Ser1177, was significantly decreased paralleled by a decreased phosphorylation of Thr495. These alterations were accompanied by a significant decrease in the density of the nitrotyrosine signal. An increase in oxidative stress measured by 8-Isoprostan could not be shown. After application of angiotensin 2 (10 mM) for investigation of the AT1-receptor dependent eNOS stimulation, we did not find differences between the increase in eNOS translocation-activation in the non-diabetic (+26.6%) and in the diabetic group (17.3 %) after two minutes of incubation with angiotensin 2. Conclusions: The present study indicates that type 2 diabetes goes along with a decrease in eNOS phosphorylation at serine1177 under basal conditions in cardiac tissue. Whether this may be attributed to the insulin-resistance of cardiac muscle has to be further investigated. Receptor stimulated eNOS- activation still works at least for angiotensin- dependent eNOS activation.