Size and characteristics of home range are fundamental ecological parameters for a species and useful life-history variables for predicting the number of individuals that can occupy a certain area. In Italy, wildlife biologists have largely ignored spatial behaviour of the European pine marten, although this predator is present across the peninsula. We investigated the seasonal socio-spatial behaviour of pine marten in a sub-Mediterranean deciduous oak forest of central Italy, by radio-tracking 16 pine martens (eight males and eight females). To our knowledge, our research is the only published study on spacing pattern of pine marten in sub-Mediterranean deciduous oak forests and the first published radio-telemetry study on pine marten home range in Italy. Size, composition and stability of seasonal ranges (FK 95 and 50 %) were analysed in both sexes. Unlike reports in the literature for other European habitats, home ranges resulted similar in size and forest coverage in both sexes and throughout seasons. The only exception were females’ territories whose size decreased in spring. Males and females occupied ranges stable in both position and size through the year, leading us to hypothesise that the sub-Mediterranean deciduous oak forest was able to meet resource requirements for both sexes and in all seasons. Our results provide useful information on the socio-spatial ecology of the European pine marten and may be helpful for conservation management of this species in southern Europe.