Between 2004 and 2006 seven adult Lesser Spotted Eagles (five males and two females) were fitted with GPS satellite transmitters. Their home ranges and territorial behaviour were analysed from 2,976 GPS fixes and field observations in the breeding area. The territories of the four males tracked in a single season had a minimum extent of 32.78 km² (D), 34.14 km² (BS), 46.40 km² (LA) and 54.39 km² (BT) respectively. The fifth male (S), which could be tracked for two years, had a home range of 93.78 km² in 2005 and 172.29 km² in 2006. The mean extent of all six territories was over 72.29 km². The home ranges used by the two females were very different in size (1.56 km² and 82.30 km²), although both individuals reared a young bird. The successful male breeders had a strong sense of territory with no overlap between them. The females, on the other hand, were not driven off from other eyries and did indeed visit the immediate vicinity of other nests at some considerable distance from their own. After brood failure, territories of unsuccessful breeders were taken over in part by neighbouring successful breeding pairs. The maximum distance from the eyrie at which the presence of adults could be confirmed was some 6–7 km for three males (D, BT and LA), some 11 km for one female (W) and one male (BS), and for male S, with the most GPS fixes, over 13 km. The size of the home ranges, and the distances from the eyrie to which the birds moved from the nest, were not constant throughout the whole stay of the birds in the breeding territory. After its arrival in spring, male S distanced itself continually further from the eyrie. In both years it moved furthest from the nest, and had the most extensive home range, in mid July. From then on, until the start of autumn migration, the area of activity became increasingly smaller. The home ranges were used to a different degree of intensity. In 2005, 84% of the 677 fixes of male S were made over an area of only 14.24 km2. In 2006, the bird was located in 71% of 989 fixes over an area of 15.43 km2. A protected zone encompassing a radius of 3 km from the eyrie is considered to be not sufficiently extensive to effectively prevent the extinction of this endangered species. In a zone of at least 6 km around the eyrie no radical changes (building of wind farms, motorways, roads, cycle paths, housing etc.) should be permitted. Keywords: Lesser Spotted Eagle Aquila pomarina, home range, GPS satellite telemetry, behaviour, Germany.