The crested porcupine is a large rodent living in Central and North Africa, with a European distribution limited to Italy. Its biology and particularly its den-ning habits are inadequately known. Our study was carried out in a Mediterra-nean coastal area of central Italy. We radiotagged 13 adult porcupines, assessing their den site selection and use each month, from February 1998 to September 1999. Porcupines preferred steep, compact soils covered with dense vegetation, for denning. Each den was always used by the same 2 individuals, possibly form-ing a reproductive pair. Paired individuals seemed to show a greater site fidelity than single ones. Intepretations of this behaviour are discussed.