The new species Cortinarius erythrofuscus Mahiques & A. Ortega (subgen. Telamonia, sect. Firmiores) is proposed. Its morphological characters are compared with similar taxa (e.g. Cortinarius petroselineus Chevassut & Rob. Henry and Cortinarius casimiri (Velen.) Huijsman). Its taxonomic inclusion in section Firmiores (Fr.) Henn. (subgen. Telamonia (Fr.) Trog) is discussed.