The White-fringed Antwren lives mainly in wooded areas and edges. The adult male has dark grey-brown upperparts. The wings are darker, rather brownish-black, with tipped white coverts. On the underparts, chin, throat, breast and belly are black. Breast sides and flanks are white. The under-tail feathers are black tipped white. The underwing coverts are white, whereas flight feathers are black.
White-fringed Antwrens feed mainly on insects and spiders. They often forage in pairs, hopping and gleaning prey from foliage and twigs. They may be seen sometimes in small mixed flocks.