This study was conducted to evaluate the effect of ensiling and /or exogenous fibrolytic enzyme supplementation date press cake using in vitro batch culture technique . Untreated date press cake (DPC) and ensiled DPC with exogenous fibrolytic enzymes (ZAD1 and ZAD2) and with or without adding urea compared to corn grains were in vitro evaluated using batch culture technique. DM, NDF and ADF degradation and total gas production as well as fermentation parameters of the incubated samples were determined after 24 h of fermentation. Total VFAs, proportions are not affected (P > 0.05) by any of the treatments. However, value of ammonia concentration was higher (P < 0.05) with ZAD2+U group and urea group than date press cake (DPC). The pH value was highest (P>0.05) with the ensiling treatments. There were no significant differences in the values of DMD and OMD between the different treatments. But, the values of NDFD and ADFD were increased (P<0.05) in the corn group. Total gas production had no difference (P>0.05) between the corn grain and the DPC without any treatments. While, values of metabolizable protein (MP) and efficiency of microbial biomass production (EMP) were increased (p<0.05) with DPC compared to corn grains . There was no significant difference in the rumen activity when using date press cake (DPC) or corn grains. Moreover, the ensiling process did not cause a clear improvement in rumen fermentation.