Despite identification of arsenic intake from well drinking water in developing countries as a crucial hazard for health, the health effects of diet-mediated intake of arsenic on health in developed countries have remained unclear. The Japanese diet, which is regarded as a healthy diet, includes a high intake of seafoods that contain high levels of arsenic. The associations among intake of Japanese food including 54 food items classified into 6 categories, arsenic exposure and hypertension were investigated in 2,709 adults in Japan. Logistic regression analysis including serum sodium and potassium levels as confounders indicated a positive association between fasting serum level of arsenic (fsl-As) and prevalence of hypertension. Seaweed, bone-edible small fish and fish meat in seafoods were strong contributors to the increased fsl-As among the food items examined. Fish meat intake was identified as the greatest contributor to prevalence of hypertension. Since 94% of arsenic has been reported to be caused by dietary intake in Japan, our results suggest that increased fsl-As caused by intake of fish meat could be a potential risk for hypertension. Considering the worldwide trend of increased fish meat intake, arsenic in fish meat might be a new global hazardous material.