Abstract: A new polypore, Antrodiella citrinella Niemelä & Ryvarden, is described. It resembles A. semisupina (Berk. & Curtis) Ryv., but is more distinctly effused, has wider pores, smaller spores and a citric yellow colour. The species is reported from Norway (type), Finland, Poland and Yugoslavia, on Picea abies (all countries) and Abies alba (Poland only). Most collections were made beside dead fruit bodies of Fomitopsis pinicola (Swartz: Fr.) Karst., one adjoined Gloeophyllum odoratum (Wulf.: Fr.) Imaz., and were growing on brown-rot caused by them, although A. citrinella itself is considered to cause white-rot. The new species is illustrated, and the concept of the genus Antrodiella is discussed.