Mixtures of polycarboxylic acids and their salts with sodium tripolyphosphate and sodium pyrophosphate have been investigated in the presence of ammonium oxalate and sodium carbonate. Some of these mixtures demonstrated good chelating power synergy and some mixures inhibited the chelating power of the individual components from which the mixures composed of. The chelating power synergy of some mixtures can be used for enhancing the function of the builders and consequently decrease the weight of the detergent meanwhile the inhibition of the chelating power in the other mixtures can be used for precipitating their components in the treated water in optimum conditions. It is worth to mention that the chelating powers of sodium tripolyphsphate and citric acid increased as many as 3-88 times by changing some experimental conditions.