Evolution of both catechin and epicatechin grape seed content was established for ten white and six red grape varieties during the ripening period. Chemometric techniques (cluster analysis and partial least squares analysis) were used for data analysis. An initial increasing stage and a final stabilisation step for both compounds have been observed for most varieties during ripening, including both red and white grape varieties. On the other hand, three red varieties (Tintilla de Rota, Tempranillo and Graciano) and two white varieties (Vijiriega and Muscat á Petit Grain) kept away from the rest showed particular trends. Graciano was the only cultivar that presented differences in catechin and epicatechin behaviour during its ripening period.