Background: The role of inflammation in the pathogenesis and progression of atherosclerosis has been increasingly discussed. Although the seroepidemiological studies have suggested a relationship between Helicobacter pylori (H. pylori) infection and atherosclerosis; the issue is still controversial. It is well known that abnormal lipid profil is related to atherosclerosis and the measurement of carotid-intima media thickness (CIMT) is one of the surrogate marker of atherosclerosis. The serum concentration of high-density lipoprotein (HDL-C) has been known to have an inverse correlation with the development of atherosclerosis. Paraoxonase-1 (PON1) is a major anti-atherosclerotic component of HDL-C. PON1 activity is related to lipid peroxidation and prospective cardiovascular risk. The aim of this study was to investigate CIMT and serum PON1 activities along with lipid parameters in H. pylori positive and negative subjects.