Reactions of trithiocyanuric acid with a large excess of ethylene oxide and propylene oxide in DMF solution and in the presence of triethylamine as catalyst were carried out. Trifunctional polyetherols containing an s-triazine ring were prepared. The structure of the products was confirmed by using elemental analysis, H-1-NMR and IR techniques. Some of the physical properties and thermal stability of polyetherols were analyzed. (C) 2000 John Wiley & Sons, Inc.