The ability of Hymenoscyphus ericae to produce 12 carbohydrolytic activities has been investigated during growth under solid-state fermentation conditions. The fungus produced a complete cellulase enzyme complex (cellulase, cellobiohydrolase and β-D-glucosidase) along with components of the hemicellulolytic (endoxylanase, β-D-xylosidase, α-L- and β-L-arabinosidase and glucoronidase) and mannanolytic (mannanase, β-D-mannosidase, α-D- and β-D-galactosidase) complexes. Specific activities were greatest for endo-acting enzymes and lower for exo-acting and side-branch removing activities in each case. The data indicate that H. ericae possesses a considerable ability to degrade plant polymeric material and are discussed in relation to establishment of the symbiosis and interaction of mycelium with moribund plant organic matter in soil.