Polymerization of propylene oxide was performed in good yield and a high isotactic content of 58.0-70.6% by calixarene-neodymium complex 2/Al(i-Bu)(3)/H2O catalyst system under the following conditions: [PO] = 4 mol/l; [PO]/[Al] = 300; Al/Nd = 6-16; temperature, 70 degrees C; reaction time, 22 or 46 h and solvent, toluene.