Eighteen male crossbred Friesian steers aged 15 months with (ILBW) of 286.91±6.01 kg were collected and divided into three similar groups (six in each). The objective was to study performance of steers using probiotic bacteria or allzyme in ration. Trail lasted about 150d. Each animal was fed individually a basal ration 65% CFM+25% CS+10% alfalfa hay on DM basis (T1,control) or 5g probiotic bacteria/h/d (T2) or 4g allzyme h/d (T3). Animals fed ration supplemented with probiotic bacteria (T2) appeared the highest significant (P<0.05) in DM, OM, CP, CF and EE digestibility. The nutritive values as TDN and DCP were (P<0.05) higher in (T2) and (T3) than control (T1). While Ruminal pH records at 0 and 3 hrs decreased significantly (P<0.05) with (T2) and (T3) compared to (T1). Also, the concentration of NH3-N decreased. However, TVFA's concentration in rumen liquor at 0 and 3 hrs with (T2) and (T3) were higher than (T1). Probiotic bacteria or allzyme led to significant increase (P<0.05) in total protein and globulin with decreasing albumin. The DMI tended to increase with T2 and T3. Whereas, the intake of TDN and DCP increased significantly (P<0.05) in (T2 and T3) than (T1). Feed supplementations showed significant (P<0.05) enhancement in feed conversion. Economic efficiency was high for T2 and T3 compared to T1. It could be summarized that adding probiotic bacteria and allzyme to fattening steers rations led to improve digestibility coefficient, rumen fermentation activity, blood parameters and feed intake, tended to increase DWG, feed efficiency and economic efficiency.