The aim of this study was to describe the feeding habits of the garden dormouse Eliomys quercinus in orange groves of eastern Spain. The study area was an extensive orange grove near Sagunto (Valencia, Spain). This study combines two different non-invasive methods, the study of food store remains and the macroscopic analysis of feces. A total of 527 feces and the food remains of 172 food stores were recollected from nest boxes. Each feces was classified into five categories according to its characteristics: arthropods, gastropods, oranges, plants, and others. Throughout the year, the garden dormouse consumed all these types of food. The most consumed prey in summer and autumn were insects. However, in winter and spring orange fruit was the principal food type. Seasonal variation of orange, arthropods, gastropods, and plant matter consumption occurred. Among animal prey types, insects were the most consumed group and large-sized species were preferred. Vertebrate preys were found in food stores. The annual variation of the garden dormouse diet owing to the seasonal availability of resources in an agricultural environment revealed its feeding behavior plasticity.