Habitat preferences of alpine marmots, Marmota marmota, were investigated at two sites in the French Alps. The use of a logistic-linear model allowed us to model the probability of marmot settlement in different ecological situations. Marmots preferred sites with a southern or eastern aspect (where snow melts relatively early), intermediate slopes, moderate plant cover, and a low level of human disturbance, and they seemed to select their habitat according to a nested system. To test if habitat quality affected individual fitness, we investigated the effects of sun exposure and two home-range characteristics on litter size at emergence, frequency of female reproduction, and retention of subordinates. Sun exposure and home-range size are two major components of home-range quality that may affect individual fitness.