A new, one step functionalization of C60 with lactones has been developed. This photochemical approach utilizes a variety of lactonyl radicals deriving from lactones through a hydrogen atom abstraction process mediated by tetrabutylammonium decatungstate [(n-Bu4N)4W10O32]. This reaction provides access to a previously unknown class of materials, namely 1-lactonyl-2-hydro[60]fullerenes. A mechanism for this new reaction has been proposed based mainly on the structure of reaction products and deuterium-incorporated experiments.