The diet and pattern of food resource use by the pygmy skunk Spilogale pygmaea, an endemic and threatened species of western Mexico, was evaluated in the tropical dry forest of Chamela, Jalisco. Analysis of scats (n = 104) and stomach contents (n = 5) obtained during 1997, 1998 and 2000 showed that pygmy skunks fed mainly on invertebrates. Insect larvae constituted the most represented food item in samples. During 2000, food resource use was quantified by comparing occurrence of available prey with occurrence of items found in scats. Even though pygmy skunks seem to be opportunistic foragers, some invertebrates were positively selected, such as insect larvae and Myriapoda, thus suggesting that pygmy skunks may target prey of high nutritional value. The diet varied considerably between consecutive dry and rainy seasons of the studied years, with little overlap in food items. Pygmy skunks may adjust food resource use in response to temporal variations in prey abundance, by incorporating other food items in their diet during the dry season, when food is scarce. Dietary switching between seasons indicates that pygmy skunks may exhibit strategies similar to those of other tropical carnivores to deal with a highly seasonal environment.