A series of new phosphate type of amphoterics having a 2-hydroxyalkyl group as a hydrocarbon chain, 2-(N-2-hydroxyalkyl-N,N-dimethylammonio)ethyl hydrogen phosphates (alkyl[R]:dodecyl, tetradecyl, hexadecyl), was synthesized and their physicochemical properties—isoelectric point, critical micelle concentration (CMCs), occupied area/molecule at interface and the change of free energy of micellization—and antimicrobial properties were investigated in comparison with those of sodium 2-(N-alkyl-N-methylamino)ethyl hydrogen phosphates. It was found that the CMCs and the occupied areas were observed to decrease due to a phosphobetaine moiety and a 2-hydroxyethyl group. Solution properties of the binary system of SDS/2-(N-2-hydroxytetradecyl-N,N-dimethylammonio)ethyl hydrogen phosphate in aqueous solutions were studied in terms of surface tension and pH value. On the other hand, it was observed that the Minimum inhibitory concentration (MICs) of 2-(N-2-hydroxyhexadecyl-N,N-dimethylammonio)ethyl hydrogen phosphate against fungi were smaller than those of chlorhexidine diglucon