Abstract: Transition metals form a plated deposit in an electroless transition metal plating bath containing an organophosphorus complexing agent selected from the class of compounds having the general formulas: ##STR1## wherein R.sub.1 is alkyl having from 1 to 5 carbon atoms, alkali metal and ammonium salts of said compounds, and ##STR2## wherein R.sub.2 is ##STR3## R.sub.3 is selected from the class consisting of R.sub.2 and --CH.sub.2 CH.sub.2 OH, and R.sub.4 is selected from the group consistiong of R.sub.2, --CH.sub.2 CH.sub.2 OH, and ##STR4## wherein each M is independently selected from the group consisting of H, NH, and alkali metal, and "n" is an integer from 1 to 6 inclusive. These baths have unique properties, including the ability to be formulated to have selected operating pH values within a wide pH range and the ability to operate effectively at the selected pH value.