Introduction: Physical inactivity is one of the major worldwide health concerns. Associations of sedentary behavior with cardiovascular diseases have been reported; however, there are few reports from Japanese population where obesity is less prevalent compared with Western populations. We investigated the association of sedentary behavior with cardiometabolic risk factors in a Japanese representative population. Methods: This is a cross-sectional study of 2,402 general Japanese populations (1,050 men, 1,352 women, aged 20 years and older) (the National Integrated Project for Prospective Observation of Non-communicable Disease And its Trends in the Aged 2010; the NIPPON DATA2010), who participated in the National Health and Nutrition Survey of Japan conducted in 2010. The most usual ways to spend time of the day for each participant were collected from self-completion questionnaire and interview by trained interviewers in the baseline survey of NIPPON DATA2010. The physical activities were categorized into vigorous physical activity, moderate physical activity, slight physical activity, TV-viewing, sitting, and basal level of activity. Sedentary time was calculated as the sum of TV-viewing and sitting time. Odds ratios and 95% confidence intervals for each cardiometabolic risk factors according to the tertiles of sedentary or TV-viewing time were estimated by logistic regression models, adjusting for age, smoking status, drinking status, residential area, and equivalent household expenditure. Results: The medians (25th percentiles, 75th percentiles) of sedentary time (hours/day) and TV-viewing time (hours/day) were 5.0 (3.0, 7.5) and 3.0 (2.0, 4.0) in men, and 4.5 (3.0, 7.0) and 2.0 (1.0, 3.5) in women, respectively. In total, sedentary time was positively associated with high triglycerides (OR [95% confidence intervals]: 1.30 [1.01-1.66]) and low HDL cholesterol (1.50 [1.08-2.07]), and TV-viewing time was positively associated with high triglycerides (1.65 [1.27-2.15]), low HDL cholesterol (2.09 [1.46-3.00]) and high LDL cholesterol (1.32 [1.05-1.66]). In men, sedentary time and TV-viewing time were positively associated with low HDL cholesterol (1.98 [1.13-3.49], 1.99 [1.13-3.53], respectively). In women, sedentary time was positively associated with high triglycerides (1.61 [1.09-2.37]), and TV-viewing time was positively associated with obesity (1.64 [1.13-2.38]), high triglycerides (1.96, [1.29-2.98]), low HDL cholesterol (2.05 [1.27-3.30]) and high LDL cholesterol (1.41, [1.02-1.95]). There were no significant associations of sedentary or TV-viewing time with hypertension and diabetes after adjusting for age. Conclusions: In conclusion, sedentary behavior including TV-viewing was positively associated with cardiometabolic risk factors, especially dyslipidemia in general Japanese population.