This experiment was conducted to determine the nutritive value of spent wheat straw compost from Pleruotus Ostreatus mushroom production as ruminant feed. The compost was provided from mushroom unit production in the Khanasry station in Jordan ,then it was sun dried and sampled for chemical analysis ,in vitro digestion and In vivo digestion  for untreated cereals straw and spent cereals straw was done. Fungal treatment increase CP from 3.7 in the untreated cereals straw to 13% in the spent cereals straw, ash increase in the spent cereals  straw and OM,NFE, NDF,ADF,ADF,cellulose and hemicellulose were  decreased in the spent cereals straw. In vitro digestion was lower for DM and OM in spent cereals straw. No significant differences in the in vivo digestion of DM, OM, NDF were found and ADF.CP digestion was significantly lower (P<0.0) in spent cereals straw. N-Balance was negative and significantly (P<0.01) lower for spent cereals straw.