Water-soluble complex between C-60 fullerene and cholesteryl group-bearing pullulan (CHP) was prepared. C60 fullerene was dissolved in pyridine (10% v/v) in advance and then mixed with an aqueous CHP suspension (0.1 mg ml(-1)). The particle size of the formed complexes varied from 60 nm to 150 nm by the concentration of aqueous pyridine in final solution. The complex; could retain its integrity for a long period of time without destruction upon heating or freezing.