Excessive oxidative stress and abnormal blood lipids may cause chronic diseases. This risk can be reduced by consuming an antioxidant- and fiber-rich vegetarian diet. We compared biomarkers of oxidative stress, antioxidant capacity, and lipid profiles of sex- and age-matched long-term vegetarians and omnivores in Korea. Forty-five vegetarians (23 men and 22 women; mean age, $49.5{pm}5.3$ years), who had maintained a vegetarian diet for a minimum of 15 years, and 30 omnivores (15 men and 15 women; mean age, $48.9{pm}3.6$ years) participated in this study. Their 1-day, 24-h recall, and 2-day dietary records were analyzed. Oxidative stress was measured by the levels of diacron reactive oxygen metabolites (d-ROM). Antioxidant status was determined by the biological antioxidant potential (BAP) and levels of endogenous antioxidant enzymes such as superoxide dismutase, catalase, and glutathione peroxidase. We observed that vegetarians had a significantly lower body fat percentage ($21.6{pm}6.4%$) than that of omnivores ($25.4{pm}4.6%$; $P$ < 0.004). d-ROM levels were significantly lower in vegetarians than those in omnivores ($331.82{pm}77.96$ and $375.80{pm}67.26$ Carratelli units; $P$ < 0.011). Additionally, total cholesterol levels in the vegetarians and omnivores were $173.73{pm}31.42$ mg/dL and $193.17{pm}37.89$ mg/dL, respectively ($P$ < 0.018). Low-density lipoprotein cholesterol was $101.36{pm}23.57$ mg/dL and $120.60{pm}34.62$ mg/dL ($P$ < 0.005) in the vegetarians and omnivores, respectively, indicating that vegetarians had significantly lower lipid levels. Thus, oxidative stress, body fat, and cholesterol levels were lower in long-term vegetarians than those in omnivores.