This study investigated the relationship between smoking habits and serum levels of 8-OHdG, oxi-dized LDL antibodies (oLAB), Mn-SOD, and carotenoids. Subjects were 79 males (mean age ± stan-dard deviation; 62.1 ±10.0 years) and 79 females (60.3±10.3 y) who attended a health examination screening in the town of Hokkaido, Japan. Serum 8-OHdG, Mn-SOD, and oLAB levels were measured by ELISA and serum carotenoids levels were measured by HPLC. Smoking habits were assessed by public health nurses using a questionnaire. Serum 8-OHdG levels were significantly higher in males than in females. On the other hand, serum levels of β-carotene, α-carotene, β-cryptoxanthin, and zeaxanthin and lutein were significantly lower in males than in females. Serum β-carotene, β-cryptox-anthin, and zeaxanthin and lutein were significantly lower in males who were en-aut-name=Junichi Ochiai, Kunio Aoki, Kenji Wakai, Akiko Tamakoshi, Masahiko Ando, Yoshiyuki Watanabe, Kotaro Ozasa, Nao Seki, Yoshikazu Nishino, Takaaki Kondo, Yoshiyuki Ohno3 for the JACC Study Groupcurrent smokers, com-pared to non-smokers. Serum 8-OHdG levels were also significantly higher in current smokers.Furthermore, in males, serum oLAB and β-carotene levels were significantly and negatively correlated with the number of cigarettes smoked per day. Serum Mn-SOD levels were unrelated to smoking habits in males. In conclusion, this preliminary study suggests that cigarette smoking increases serum 8-OHdG levels and reduces serum levels of oLAB and carotenoids, such as β-carotene, β-cryptoxan-thin, and zeaxanthin and lutein in healthy male subjects. Serum levels of 8-OHdG, oLAB, and carotenoids may be useful biomarkers of oxidative conditions affected by smoking. J Epidemiol2003;13:29-37.