Snakes usually exhibit seasonal variations in movement patterns, home-range size and habitat use. This study evaluates the seasonal variation in movement rates, home-range size, habitat use, and microhabitat use by male Lataste's Vipers (Vipera latastei) in northern Portugal using radio-telemetry. Estimates of movement rate revealed short movements (5.4 m/day) and small home range size (0.24 ha) throughout the year, except in September when there was an increase in both movement rates (21.5 m/day) and home-range size (1.52 ha). Male vipers used different habitats and microhabitats during the year: forested areas for hibernation, open forest with bushes for foraging, and in the proximity of water in the summer.