Abstract Few studies have described the natural history of Phrynops geoffroanus in anthropogenic environments. We analyzed the stomach contents of 39 P. geoffroanus from the Anhanduizinho River, Campo Grande, Mato Grosso do Sul, Brazil, from September 2004 to April 2005. We verified the presence of invertebrates (Odonata larvae and mollusks), fish, and plant material. The primary food item ingested all year by the P. geoffroanus examined was the larval stage of Chironomus sp.