The domestic cat Felis silvestris catus is considered a potential threat to the native fauna of regions it populates, particularly when it has free access to these areas. Although this problem is known in Brazil, little is known regarding the effects of this species on natural areas. This study aimed to obtain information concerning the diet of domestic cats by identifying the main items found in fecal samples from domestic cats. In addition, the effects of seasonality on the diet were examined, as it has been hypothesized that seasonal variation of food items has little influence of the diet of the domestic cat. These semi-domiciled cats are thought to face a constant and continuous supply food offered by their owners throughout the year. Feces were collected in a remnant fragment of an Atlantic Forest located south of the municipality of Ilha Comprida — SP, Brazil. These samples provided important information regarding the dietary ecology and predation behavior of this species in endangered forest areas. The results of the scat content analyses demonstrated that domestic cats inserted in this biome presented a generalist and opportunist diet with little seasonal variation, even when receiving food from their owners. The most frequently consumed groups of prey were insects (20.8%) followed by mammals (13.9%) and birds (4.0%). Although the cat is not the only factor that impacts the species of the region, management programs need to be established in conjunction with the local community with the aim of minimizing the pressure exerted by these animals on the native fauna.