On the influence of alkyl and carboxymethyl groups on the building performance of chelating-type polycarboxylic acids were studied. The following ether polycarboxylates were prepared by the reaction of the corresponding alcohols with ethyl diazoacetate or some other reagents, and their building performances were compared with those of sodium tripolyphosphate (STPP) and disodium oxydiacetate (ODA-Na) in a detergent system formulating alkylbenzenesulfonate (LAS) : Sodium t-butoxyacetic acid (TBA-Na), disodium 4, 5-dimethyl-3, 6-dioxaoctanedioate (BGDA-Na), disodium 4, 4-dimethyl-3, 6-dioxaoctanedioate (IBGDA-Na), disodium 4, 4, 5, 5-tetramethyl-3, 6-dioxaoctanedioate (PDA-Na), disodium 4, 5-diethyl-3, 6-dioxaoctanedioate (HGDA-Na), disodium 4, 8-dimethyl-3, 6, 9-trioxaundecanedioate (DPGDA-Na), disodium 4, 7-dimethyl-3, 6, 9-trioxaundecanedioate (IDPGDA-Na), disodium 3, 6, 9-trioxaundecanedioate (DEGDA-Na), disodium 5, 5-dimethyl-3, 7-dioxanonanedioate (NPGDA-Na), trisodium 4-methyl-5-carboxylatomethoxy-3, 7-dioxanonanedioate (MGTA-Na), tetrasodium 5, 6-bis (carboxy-latomethoxy) -3, 8-dioxadecanedioate (ETTeA-Na), tetrasodium 5, 5-bis (carboxylatomethoxymethyl) -3, 7-dioxanonanedioate (PETTeA-Na), and hexasodium 5, 6, 7, 8-tetrakis (carboxylatomethoxy) -3, 10-dioxadodecanedioate (SHA-Na). The detergency were tested on naturally soiled cotton patches and the detergency powers were evaluated by the Scheffe's method.From the results summarized in Fig.-1, it is evident that the ether polycarboxylates containing methyl groups show the building performance much superior to that of the corresponding ether carboxylates without methyl groups. The building performance of disodium 4, 4, 5, 5-tetramethyl-3, 6-dioxaoc-tanedioate (PDA-Na) was similar to that of STPP. On the building performance of the ether polycarboxylic acids methyl groups were most effective when the methyl groups were introduced to the carbon bonding carboxymethoxyl groups. The introduction of carboxymethoxyl groups to such places was also effective, but its effect was less than that of methyl group.