A series of water-soluble fullerene C(60) derivatives has been investigated for their cytotoxic and hemolytic properties, with the aim to correlate structure with toxicity. We observed that cationic chains induce significant toxicity while the presence of neutral or anionic moieties did not produce any response in our model. A validation of these experimental observations has been performed by theoretical studies in which hydrophilic and hydrophobic surface areas were correlated quantitatively with hemolytic properties.