Oxidative stress markers may be novel factors contributing to cardiovascular (CVD) risk. The purpose of this study was to examine the effects of long-term exercise, age, and their interaction on the plasma levels of the oxidative stress markers oxidized LDL (ox-LDL), nitrotyrosine, and myeloperoxidase (MPO), and to investigate whether these levels correlated with plasma NOx levels. Older (62 ± 2 yr) active (n=12) men who had exercised regularly for over 30 years and young (25 ± 4 yr) active (n=7) men who had exercised regularly for over 3 years were matched to older (n=11) and young (n=8) inactive males. Young subjects showed lower plasma nitrotyrosine levels than older subjects (P = 0.047). Young inactive subjects had higher ox-LDL levels than either the young active (P = 0.042) or the older active (P = 0.041) subjects. In addition, plasma oxidative stress levels, particularly ox-LDL, were correlated with various conventional CVD risk factors, and in older subjects were associated with Framingham risk score (r = 0.49, P = 0.015). The study found no relationships between plasma markers of oxidative stress and plasma NOx levels. The findings suggest that a sedentary lifestyle may be associated with higher ox-LDL levels and that the levels of oxidative stress markers may contribute to CVD risk.