ABSTRACT The spatial and trophic ecology of the culpeo fox (Lycalopex culpaeus) was studied in the Salar de Punta Negra basin and the Llullaillaco National Park, in the high Andes of the Region of Antofagasta in northern Chile. The objectives of this study were to understand the feeding ecology, habitat use, and home range and activity pattern of culpeo fox. The study was conducted in an area of approximately 2800 km2 inside the Punta Negra salt flat basin, Llullaillaco NP, the surrounding mountains, and within areas of mining operations. We used methodologies including camera trapping, live trapping and satellite monitoring of L. culpaeus individuals, and diet analysis. Fifteen captures and five recaptures of culpeos were made, and three of them were equipped with satellite tracking collars. The home ranges estimated using the Minimum Convex Polygon (MPC 95%) were: 1029 km2 (female), 809 km2 (female) and 215 km2 (male). Culpeo foxes were nocturnal animals. A larger sample of 282 fecal scats was collected, with the main trophic prey in culpeo fox diet by frequency of occurrence being rodents (74.3%), arthropods (48%), camelids carrion (43.6%), birds (16.3%), vegetation (13.8%) and reptiles (2.5%). Niche breadth was low (0.367).