A precise and sensitive HPLC method, with diode array detection, for phenolic compounds in white juices and wines is presented. Eighteen of these phenolics have been identified and quantitated in white free run juices and 19 in white wines. Identification of benzoic acids was confirmed by GC/ MS. The only flavonol detected, quercetin 3-glucuronide, was identified by TLC and electrospray (ESI) techniques. Levels of the trans- and cis-hydroxycinnamic acids, flavonoids, and benzoic acids present in white juice and wine are reported. Hydroxycinnamates were the major phenols; among them, trans-caftaric, trans-coutaric, and cis-coutaric were the predominant. The cis-coutaric represented a substantial percentage in the total amount of phenols. Flavonoids were present at low concentration, and benzoic acids were the minor compounds. During white vinification, a significant decrease in the phenolic compounds present in free run juice was observed, mainly caused by the hydroxycinnamic acids.