This study was conducted to evaluate the feeding value of the spent mushroom (Hypsizygus marmoreus) substrates(SMS) in laying hens (Hy-Line Brown). The fresh spent mushroom (Hypsizygus marmoreus) substrates collected from theNamkyung farm were fermented with Bacillus subtilis EJ3 for 2 weeks. A total of twenty-four laying hens were fed corn-soy basedexperimental diets containing 0% (T0), 5% (T1), 10% (T2) and 15%(T3) fermented SMS for 12 weeks. There were no significantdifferences among the treatments in egg production, egg weight, egg mass, feed conversion and viability during the experimentalperiod. Feed intake was significantly lowered in T0 (118.3 g) than T1 (121.9 g), T2 (120.3 g) and T3 (122.4 g). There were nosignificant differences among the treatments eggshell breaking strength, thickness and haugh unit, whereas the yolk color of T1,T2 and T3 were significantly heavy than T0. The palatability of boiled meat was significantly better in the T3 laying hens than inthe T0 laying hens. In conclusion, fermented SMS can be used as resource of feed in laying hen feed at 5.0-15% level withouteffect on performance and egg qualify.