This study was carried out to investigate the effect of partial or all replacement of berseem hay by Moringa oliefera stems. Fifteen of lactating Friesian cows with average live body weight of 500 kg (2-4 seasons of lactation after the peak milk yield) were fed covering their requirements recommended feeding allowances for dairy cows. Animals were divided into three groups (5 each) assigned randomly to three experimental rations. Control ration (R1) consisted of 40% concentrate feed mixture (CFM) + 20% corn silage (CS) + 20% rice straw (RS) + 20% barseem hay (BH), While the other rations contained 10 and 20% Moringa oliefera stems (MS) instead of 50 and 100% of BH in R2 and R3, respectively. Results revealed that the contents of CP, CF and ash tended to increase, however the contents of OM, EE and NFE tended to decrease with increasing the level of Moringa oliefera stems in the rations. Digestibility of DM, OM and CP of 10% MS-ration (R2) were significantly higher than those of control ration (R1) and insignificant higher than those of 20% MS-ration (R3). Otherwise, digestibility of CF and NFE as well as TDN value did not affected significantly by treatments. The value of DCP was significant higher with both tested rations than that of control. Totally, digestibility of most nutrients and feeding values were the highest with R2 and the lowest with control (R1). Daily feed intake and rumen fermentation activities were nearly similar trend among the different groups. Total protein, albumin and globulin concentrations increased significantly (P<0.05), but urea-N and creatinine concentrations in plasma decreased significantly (P<0.05) with increasing the level of Moringa stems in the rations. Daily yield of actual milk and 4% FCM as well as the percentages of fat, protein, total solids and solids not fat in milk increased insignificantly (P>0.05) with 10% MS-ration (R2) and significant increased (P<0.05) with 20% MS-ration (R3) compared with control ration (R1). Feed conversion was insignificant improved by the ration included the low level of MS (R2), but the improvement was significant with the ration having the high level of MS (R3) than that of control one (R1). Also, Moringastems reduced the average daily feed cost and feed cost per one kg 4% FCM, but increased the price of 4% FCM yield and subsequently economic efficiency.