A new 2-aza-anthraquinone 6-O-demethyl-5-deoxybostrycoidin was isolated from cultures of a yellow mutant of the fungus Nectria haematococca grown in a medium enriched in asparagine. The results obtained with this family of nitrogen-containing quinones are discussed in relation to our knowledge about the biosynthesis of the other naphthoquinone pigments.