The present invention relates to additives which may be employed in electroless metal and metal alloy plating baths and a process for use of said plating baths. Such additives reduce the plating rate and increase the stability of electroless plating baths and therefore, such electroless plating baths are particularly suitable for the deposition of said metal or metal alloys into recessed structures such as trenches and vias in printed circuit boards, IC substrates and semiconductor substrates. The electroless plating baths are further useful for metallization of display applications.