4-(2-Phthalimidyl)benzoyl cyanide (Phibyl-CN) was designed as a fluorescent labeling reagent for primary and secondary alcohols in high-performance liquid chromatography. Reaction conditions were optimized with hexanol, benzylalcohol, cyclopentanol and 1-phenyl-1-propanol as model compounds of primary and secondary alcohols. Phibyl-CN reacted quantitatively with alcohols on heating at 50°C for 30 min in the presence of 4-dimethylaminopyridine to give the corresponding fluorescent esters which were separated on a reversed-phase column with fluorescence detection. The detection limits for alcohols labeled with the reagent were 0.24-0.38pmol per injection. The extents of conversion of primary and secondary alcohols into fluorescent esters were approximately 100%.