Spatiotemporally restricted gene targeting is needed for analyzing the functions of various molecules in a variety of biological phenomena. We have generated an inducible cerebellar Purkinje cell-specific gene targeting system. This was achieved by establishing a mutant mouse line (D2CPR) from a C57BL/6 mouse ES cell line, which expressed a fusion protein consisting of the Cre recombinase and the progesterone receptor (CrePR). The Purkinje cell-specific expression of CrePR was attained by inserting CrePR into the glutamate receptor delta2 subunit (GluR delta2) gene, which was expressed specifically in the Purkinje cells. Using the transgenic mice carrying the Cre-mediated reporter gene, we showed that the antiprogesterone RU486 could induce recombinase activity of the CrePR protein specifically in the mature cerebellar Purkinje cells of the D2CPR line. Thus this mutant line will be a useful tool for studying the molecular function of mature Purkinje cells by manipulating gene expression in a temporally restricted manner.