To evaluate the molybdenum (Mo) status in the Japanese population, the Mo content in various foods and human milk was determined using inductively coupled plasma mass spectrometry (ICP-MS) and the average Mo intake was estimated. The difference in Mo content among food groups was marked; Mo levels in several plant foods such as cereals were more than 0.5 g/g while those in most animal foods were less than 0.1 microg/g. In particular, Mo contents in several samples of seeds and pulses were more than mixeo 1 mirog/g. The variation in Mo contents in each type of cereal was also conspicuous. Based on the present quantification of Mo in foods and the recent National Nutrition Survey in Japan, the average Mo intake of the Japanese population was estimated as 225 microg/d/capita. The principal Mo source in the Japanese diet was rice followed by soybean products, and approximately 90% of the Mo intake was derived from plant foods. Seventeen human milk samples were collected from 3 healthy mothers once or twice a month from 96 to 327 d after delivery. The median and range of Mo in human milk samples were 4.5 ng/mL and 2.0 to 8.8 ng/mL, respectively. Mo levels in Japanese formula milk were 2 to 3 ng/mL. Based on the Mo levels in human milk and formula milk, the Mo intake of Japanese infants was estimated to be 2 to 4 microg/d/capita.