In numerous instances, the fate of a single cell not only represents its peculiar outcome but also contributes to the overall status of an organism. In turn, cell division cycle and its control strongly influence cell destiny playing a critical role in targeting it towards a specific phenotype. Several factors participate to the control of growth and among them p27 and p57, two proteins modulating various transitions of cell cycle, appear to play key functions. In this review, the major features of p27 and p57 will be described, focusing in particular on their recently identified roles not directly correlated to cell cycle modulation. Then, their possible role as molecular effectors of polyphenols activities are discussed. Polyphenols represent a large family of natural bioactive molecules that have been demonstrated to play promising protective activities against several human diseases. Their use has also been proposed in association with classical therapies for ameliorating their clinical effects and for diminishing their negative side activities. The importance of p27 and p57 in polyphenol cellular effects will be discussed with the aim of identifying novel therapeutic strategies for the treatment of important human diseases, such as cancers, characterized by an altered control of growth.