Population dynamics, breeding patterns and spatial use of the garden dormouse Eliomys quercinus were studied for 3 years in a larch woodland in the Alps. Animals were caught with live-traps, once a month from May to September, and marked with transponder tags. Population density ranged from a minimum of 8.3 individuals/10 ha to a maximum of 49.4 individuals/10 ha when juveniles became trappable. The activity season of the garden dormouse lasts 5 months and allows the animals to reproduce only once a year. Birth rates fell between the middle of June and the middle of August. The dormouse population was characterized by high stability and adults continued to live in the same area from year to year. The main factor limiting the survival of individuals was winter mortality. Survival on the trapping grid through hibernation was 36–50% for adults and c. 32% for juveniles. During the mating season, males and females were aggregated and overlapped their ranges, and after the mating season, they spread out. The tendency of the reproductive females to have separate non-overlapping ranges is indicative of a probable territorial behaviour in females during gestation and lactation.