Provided is a simple and efficient production process of a nucleobase having a perfluoroalkyl group. A nucleobase (for example, uracils, cytosines, adenines, guanines, hypoxanthines, xanthines, or the like) is reacted with a perfluoroalkyl halide in the presence of a sulfoxide, a peroxide and an iron compound to produce a perfluoroalkyl-substituted nucleobase, which is useful as an intermediate for medical drugs, economically.