A Fossil cavity with its entrance opening has been preserved in a piece of petrified wood from the Eocene of Yuma, Arizona, USA. Even in details, this trace-fossil is very close to recent cavities produced by representatives of the genus Picoides. It is therefore concluded that woodpeckers (Picinae) must be at least of Eocene age. The petrified wood has been identified to represent a species close to Acacia (Leguminosae). The trace fossil "woodpecker hole" receives the name Eocavum picifactum nov. ichnogen.