Conservation physiology is an important tool used to understand how variation in the natural environment can evoke a physiological stress response in free-living animals. The aim of this study was to analyze how fecal cortisol metabolite (FCM) levels vary in response to habitat type, prey abundance and interspecific competition in a free-living population of wildcats in northwest Spain. We collected 110 fresh fecal samples from 25 wildcats along 28 transects between May 2005 and June 2009. To determine habitat characteristics and competing carnivore abundance, we defined 110 circular plots with the fresh wildcat scat at the center. For each plot, we sampled habitat variables, competitor carnivore abundance (pine marten [Martes martes] and red fox [Vulpes vulpes]) and prey abundance (wood mice [Apodemus sylvaticus]). Our results indicate that habitat variables, interference competition and main prey abundance did not significantly affect FCM levels in wildcats.