The extractable phenolic fraction has been studied in a wide group of representative samples from the main food phenolic sources: fruits, vegetables and legumes. After quantitative extraction and quantification of each phenolic compound in the samples, the total extractable phenolic chromatographic index was defined as the sum of all extractable phenolics obtained under conventional conditions, and calculated for the main phenolic classes found in foods: hydroxybenzoic and hydroxycinnamic acids as well as flavonoids. Phenolic acids and flavonoids contents are reported for the food samples studied. The results presented in this work allow an interesting overview of the distribution of the phenolic classes in foods, as well as an approach to the knowledge of the phenolic classes composition in foods.