The aim of the study was to evaluate the effect of quinapril on HOMA-IR, high sensitive C-reactive protein and leptin. Total 54 hypertensive and 24 control subjects were included in this study. Blood pressure, leptin, high sensitive C-reactive protein, and HOMA-IR were determined at baseline and after 3 months quinapril treatment. After treatment with quinapril HOMA-IR (p = 0.04), high sensitive C-reactive protein (p = 0.027), and leptin (p = 0.046) were decreased in hypertensive patients. Quinapril may be used as a therapy for improving blood pressure as well as the insulin resistant, hyperleptinemic, and low-grade inflammatory state in hypertension.