Dehydration of several 1,3-diols into unsaturated alcohols was investigated over pure CeO 2 at 325–425°C. 1,3-Diols are more reactive than other diols and monoalcohols over CeO 2 . In the dehydration of 1,3-propanediol, 1,3-butanediol, 3-methyl-1,3-butanediol, 2,4-pentanediol, and 2-methyl-2,4-pentanediol, unsaturated alcohols are selectively produced at 325°C. In the dehydration of 2-methyl-1,3-propanediol, the corresponding unsaturated alcohol is produced with low selectivity: decomposition simultaneously proceeds. TPR experiment reveals that active CeO 2 surface is maintained at high valence of Ce 4+ in the water-producing reaction. It is speculated that redox nature between Ce 4+ –Ce 3+ affects the dehydration of 1,3-diols.