The work presented here relies on data obtained from 18 Alpine ibex (Capra ibex ibex L.), captured and GPS collared from May to August 2003 in the Vanoise National Park(France) and in the Gran Paradiso National Park (Italy). We monitored 11 males and 7 females ibex using GPS 3300S (Rev. 2) collars from Lotek Wireless Inc., scheduled with 3 hours sampling interval, till May 2004 (for the most). We extracted height, slope and exposure for each of the 16851 selected locations from a 50m resolution Digital Terrain Modeling (DTM), covering both Vanoise and Gran Paradiso National Parks, incorporated into a GIS (Arcview). We analyzed habitat used as regards relief (height, slope and exposure) by GPS collared ibex during the whole monitoring period. We present in this paper the results obtained concerning differences between sexes, on a monthly basis.