A new species, Cortinarius badiolaevis Niskanen, Liimat., Mahiques, Ballarà, Kytöv. in subgenus Telamonia, is described based on morphological and molecular data. Typical for the species is a dark brown cap, pale flesh, indistinct universal veil, small amygdaloid to ellipsoid spores [7.0–8.5 × 4.5–5.0(−5.5) µm], and dark exsiccata. It occurs in mesic to dryish coniferous forests, and grows in calcareous soil presumably with Pinus and Picea. So far, it is only known from Spain and Sweden, and considered rare. Based on the phylogenetic analyses of the ITS regions, it does not belong to any of the known sections, nor does it have any very closely related sister species.