The Eurasian Treecreeper nests in coniferous and mixed forest with large trees. The characteristic nest is placed in a narrow gap behind a piece of flaking bark, often on an old spruce or pine, and is built from twigs, bark and feathers. It also takes special nest boxes with a slit-shaped opening. The female normally lays 5–6 eggs, which she incubates for about 13–15 days. The young are fed by both parents and fledge after barely three weeks.