We determined the diet of the brown-nosed coati (Nasua nasua) in an urban semideciduous forest fragment in southeastern Brazil. Coati feces were collected weekly for 3 years. The 226 fecal samples included plant parts (85.4%), insects (75.7%), millipedes (53.9%), fruits (48.7%), spiders (33.6%), organic waste (9.7%), vertebrates (9.3%), and gastropods (2.6%). More spiders and millipedes were consumed during the wet season, and more fruits were consumed in the dry season. The consumption of vertebrates, fruits, and millipedes differed among different years. The monthly consumption of spiders and millipedes was positively correlated with rainfall. The consumption of fruits was negatively correlated with the consumption of millipedes and insects. Fruits were an important resource during periods of arthropod scarcity. Coatis ingested and defecated intact seeds of 49 plant species, indicating that they can be important seed dispersers. The consumption of vertebrates was occasional and varied.