We analyzed the diet composition of adult Common Toads (Bufo bufo) in Europe to define their general diet preferences with the use of data collected in Serbia and published data from Great Britain, Spain, France, Poland, Hungary, Belarus, and Bulgaria. We also addressed the potential correlation between adult body size and prey size, and sex-based food niche partitioning in adults as suggested by the pronounced sexual size dimorphism in this species. Analysis revealed that European Common Toads feed most frequently on insects, e.g., Coleoptera and Hymenoptera (Formicidae), but food diversity may vary among regions. A number of other invertebrate taxa were included in the diet, though usually in frequencies less than 0.1. The results suggest that the Common Toad is neither a feeding generalist, nor a myrmecophagous specialist, as some bufonids are proclaimed to be. In-depth analysis of samples from Serbia revealed no correlation between the body size of toads and the number of prey ingested, a positive correlation between toad body size and prey size due to sexual size dimorphism, high overlap of dietary preferences, and concordance in the distribution of various prey types between males and females. Furthermore, males consumed small prey items in higher proportions than did females, but the opposite was found for medium-size prey, which suggests possible dietary niche partitioning in prey size rather than in taxonomical composition.