Changes in phenolic acid contents during fruit development of Diospyros lotus L. were studied. Salicylic, 4-hydroxybenzoic, vanillic, gentistic, 3,4-dihydroxybenzoic, syringic, p-coumaric, and gallic acids were identified and quantitated by gas chromatography. The phenolic acid contents, except gallic acid, increased in September, reached its highest value at the end of September, and then decreased rapidly. The fruits harvested in June, July, August, November, and October have phenolic acid contents significantly lower than fruits harvested in late September. Gallic, salicylic, and vanillic acids were predominant and present in all stages of development, except gallic acid, for the fruits harvested at the end of November.