The aim of this experiment was to determine crude fiber content of sago by product fermented with White Root fungi and urea. The treatments were imposed in a Randomized Complete Design with three replications. The treatments were ration with: medium without White Root fungi and urea (R0), medium with White Root fungi (R1), medium with White Root fungi and 0,25% urea (R2), medium with White Root fungi and 0,50% urea (R3). Parameters measured were NDF, ADF, and lignin. The results showed that all components of crude fiber decreased during fermentation periods with White Root fungi (Pleurotus ostreatus) and urea. The average NDF content of fermented sago-by products were 57,27%, 51,25%, 52,37%, and 50,94% for R0, R1, R2, and R3, repectively. There was significant differences between R1, R2. R3 and R0 (P