The present invention provides a method for the transfection of filamentous fungal cells, comprising providing a multitude of containers, filling into each container an amount of polymer needed for the transfection, filling the cells to be transfected as well as an aqueous solution of transfection reagent into each of the containers, incubating the resulting mixture, removing the transfection reagent from the incubated mixture; and selecting the cells which have been transformed, characterized in that the total volume of the incubating mixture is less than 1 ml per container. Furthermore, the present invention provides the use of transformed filamentous fungal cells for the production of proteins or metabolites.