Serum carotenoid levels among residents with hyperglycemia who were screened in a health check-up program for the inhabitants living in a rural area of Hokkaido were compared with those with normal levels. Serum levels of alpha, beta-carotenes and cryptoxanthin were lower among those with high HbA1c newly detected than among those with a normal level, whereas the serum lipid peroxide (TBARS) level was higher in the former than in the latter for both sexes. Among males who currently smoked and drank alcohol, the intake frequency of carrot or pumpkin was significantly lower for those with high HbA1c than for the others, although no significant differences of serum carotenoid levels were observed. For the diabetes mellitus patients who were consulted in this study, and who have already been under control in the clinic, no significant differences of serum levels of carotenoids, or lipids such as total cholesterol and TBARS were shown compared with other groups. In conclusion, serum carotenoid levels might be a useful indicator of food intake and oxidative stress for the prediabetic condition since newly detected hyperglycemia tends to show lower serum antioxidant levels such as beta-carotene, and higher serum lipid peroxide levels.