Cyclamenaldehyde (III) is a valuable perfume compound which has usually been made commercially by a selective hydrogenation of p-isopropyl-α-methylcinnamic aldehyde (III). However, the hydrogenated product contains unreacted (I), which has yellow color and undesirable odor and which causes the product to be colored and to smell impure, and it is difficult to remove of (I) completely . An attempt was made by the author to hydrogenate (I) into cyclamen alcohol (p-isopropyl-α-methylhydrocinnamic alcohol) (II), which was dehydrogenated to (III) and it was confirmed that the colorless product having no impure odor was obtainable with good yield. The dehydrogenation reaction was carried out in vapor phase under reduced pressure and the composition of resulting products was investigated.