The object of this work is presented in a larger research project concerning 'New indexes to evidence the nutritional quality of small fruits' in progress at the Analytical Food Research Laboratories, University of Milan. The present paper contains data that contribute to the analytical characterization of 12 varieties of red raspberry through the high-performance liquid chromatography determination of the aglycon 'cyanidin' derived from chemical hydrolysis of berries. Even more interesting results are the proposal of the 'cyanidin volumetric index', by which it is possible to compare different red raspberry varieties with higher meaningfulness. A new possible correlation between the ratio of chromaticity coordinates 'a/b' and the cyanidin content of red raspberries has been identified.