Space use and activity of radio-collared leopards Panthera pardus (two adult males and one adult female) were monitored during 3–25 months in a prey-rich part of the Royal Bardia National Park, Nepal. Annual home ranges of the two males were 47 and 48 km2 and had an overlap of only 7%, whereas the overlap between the female's home range (17 km2) and that of one of the males was 56%. The range sizes were larger than reported from other studies in southeast Asia, but much smaller than some ranges in Africa. When comparing different studies, the sexual difference in range size increased significantly with increasing average range size. Thus, the cost by males of traversing large home ranges is probably not a determinant factor in shaping leopard communities. The female's seasonal home ranges (5.2 and 6.6 km2) were smallest during the seasons when her cubs were less than six months of age. She moved her home range closer to agricultural fields during the season when the abundant and important prey axis deer Axis axis visits these areas most frequently. No such pattern was detected among the two males. Instead they frequented human settlements throughout the year, probably in order to hunt easily accessible domestic animals. Home ranges in similar seasons in consecutive years overlapped more (female = 64%, male = 75%) than ranges in different seasons in the same year (female = 38%, male = 64%). Intensive tracking sessions of 24 hours revealed that the diel activity levels of the two sexes were similar (female: 62.3%, males: 62.6%). However, their patterns of activity were different as the males moved mainly at night (day: 1,582 m, night: 5,244 m) and the female moved similar distances day and night (day: 2,381 m, night: 2,698 m). The female may have restricted her movement at the time when conspecific males were likely to be active in order to protect her cubs from infanticide. The males moved in a more linear manner than the female, and the linear distances between radio locations from consecutive days differed significantly between the sexes (male: 3,324 m, female: 881 m), but the actual distances moved during the 24-hour cycles were fairly similar (male: 6,826 m, female: 5,079 m).