Aldosterone is involved in not only the regulation of blood pressure and renal sodium handling, but also the pathogenesis of insulin resistance, suggesting the clinical relevance of the inhibition of renin-angiotensin-aldosterone system (RAAS) in insulin resistant conditions. To better characterize metabolic implication of RAAS, we measured plasma renin activity (PRA) and aldosterone (PA) level in patient with type 2 diabetes. All other treatments and metabolic evaluations were performed at the discretion of the responsible physicians according to local guidelines. In the present study, we analyzed the data of 628 patients aged 18 or more years. Major exclusion criteria included renal failure, severe hepatic dysfunction, the use of spironolactone, and other severe systemic illnesses. Both PRA and PA were correlated with the circulating levels of serum sodium, apolipoprotein B (ApoB), high sensitivity CRP (hsCRP), and ALT. On a multivariate analysis, PA showed a significant association with ApoB (β＝0.580, p＝＜0.001), ALT (β＝0.305, p＝0.006), and sodium (β＝-0.224, p＝0.035) after adjusting for multiple factors. In subgroup analyses according to the type of RAAS inhibition, the association of PA with ApoB and hsCRP was markedly attenuated in patient treated with angiotensin-converting enzyme inhibitor (ACEi) (n＝53) compared with that in patients treated with angiotensin receptor blocker (n＝187) or with no RAAS inhibitor therapy (n＝388). Our results show that aldosterone has important implications for the pathophysiology of type 2 diabetes. Further studies are required to determine whether ACEi therapy is a metabolically better RAAS inhibition in patients with type 2 diabetes.