Manganese (Mn) is an essential trace element, necessary for development and growth of the organism. The adequate content of this element in the body determines proper metabolism of amino acids, cholesterol and carbohydrates. This mineral influences activity of several enzymes involved in metabolic and redox processes. Mn absorption and retention disturbances may participate in etiopathogenesis of some diseases and disorders. This article is a review of knowledge about the role of Mn in etiopathogenesis and prevention of selected diseases: brain disorders, diabetes, lipid disturbances and cancers.