Ectomycorrhizal fungi have been shown to improve on the phosphorus nutrition of their plant partners and acid phosphatase activities are thought to be important in the uptake process. The effect of nitrogen source and presence/absence of phosphorus in the experimental medium on acid phosphatase activity of Scleroderma sinnamariense, an ectomycorrhizal fungus associated with Gnetum spp.in Cameroon, was determined in comparison to Pisolithus tinctorius. The effect of internal mycelial phosphorus status of the inoculum on acid phosphatase activity was also studied. Results show that the absence of phosphorus in the assay medium stimulated cell bound acid phosphatase activity. Extracellular phosphatase activity was less than cell bound activity by a factor of 100. Key words: Acid phosphatase, cell-bound activity, Scleroderma sinnamariense, ectomycorrhizal fungus.