A convenient and efficient method for preparing 3, 3, 3-trifluoropropanoic acid (1) is reported. The starting material is 1-chloro-3, 3, 3-trifluoropropene (2) that can be easily transformed into 3, 3, 3-trifluoropropanal dimethyl acetal (4) on treatment with methanol and KOH followed by acid-catalyzed addition of methanol. Direct transformation of 4 into 1 was efficiently achieved with 30% aqueous hydrogen peroxide (4.0 equiv.) in the presence of ...