Abstract: The present invention relates to a novel and efficient method for manufacture of toroidal transformers, a bobbin for manufacture of toroidal transformers and a system for performing said method for manufacture of toroidal transformers. Said method for manufacture of toroidal transformers has properties superior for automated mass production and comprises the steps of arranging a coil around the periphery of at least one hollow bobbin of elongated shape and of flexible material; bending said at least one bobbin, together with said coil, so that the bobbin ends are brought towards each other, one of said bobbin ends defining an opening; and feeding a ribbon of magnetic material through said opening, so that said ribbon is being wound a required amount of tightly packed winding turns inside said bobbin until essentially the whole interior cavity of said bobbin is filled, said ribbon thereby forming a core.