Similar in appearance, all treecreepers are small birds with streaked and spotted brown upperparts, rufous rumps and whitish underparts. They have long decurved bills, and long rigid tail feathers that provide support as they creep up tree trunks looking for insects.
The Eurasian treecreeper is 12.5 cm long and weighs 7.0–12.9 g. It has warm brown upperparts intricately patterned with black, buff and white, and a plain brown tail. Its belly, flanks and vent area are tinged with buff. The sexes are similar, but the juvenile has duller upperparts than the adult, and its underparts are dull white with dark fine spotting on the flanks.
The contact call is a very quiet, thin and high-pitched sit, but the most distinctive call is a penetrating tsree, with a vibrato quality, sometimes repeated as a series of notes. The male's song begins with srrih, srrih followed in turn by a few twittering notes, a longer descending ripple, and a whistle that falls and then rises.