It is a well known fact that minera l plays an important role in the nutrition of animal and plant. The t race elements, which are a part of the mineral and exi st in a very small amount in the living bodies, include not only essential elements but also harmfu l and useless elements. In the researches up until now, physiological significance or essentiality for living body of such elements as cobalt, copper, iode, iron, magnesium, manganese, molybdenum, selenium and zinc have been investigated. Recently, researches have been conducted on the harmfu l elements such as arsen, cadmium, mercury and lead in relation to air, land and water pollu tion. Initial studies are focused on the function and distribution of trace elements in the living bodies, and their quantitative determination in animal, plant, water, soil and air must be carried out for this purpose. This report presents briefly the method of determination of t race minerals and some researches made by us.