Extra-pair copulation (EPC) behavior is widespread among birds in general, but rarely has been documented among members of the Woodpecker family. Here I report on an EPC observed between a nesting female Picoides pubescens (Downy Woodpecker) and a neighboring male for whom no nest was found. Behavioral observations aided by radio telemetry showed that the female had interacted with both her nesting partner and the extra-pair male on a regular basis in preceding months. This is only the second published account of an EPC in this species within the last 50 years. The circumstances and rarity of the behavior as shown by woodpeckers may lead to a better understanding of its evolutionary function among birds.