The current work was carried out to investigate the effect of replace different percentages of berseem hay (BH) by dried sugar beet tops (DSBT) on the performance of suckling and post weaning Friesian calves. Twenty newly born Friesian calves (10 males and 10 females) with live body weight(LBW) of 41.3±0.5 kg were used after suckling their dam's until 15 days of age, and then divided into five similar groups. The whole experimental period was lasted for 165 days where it staged for consecutive two periods, the first one (P1) was serves as suckling period from the 15th days of age until the weaning and the second one (P2) was continued from 106 to 180 days of age (post weaning period). All claves were fed a basal diet consisted of whole milk, calf starter (CS), BH and DSBT during P1. Consecutively, CS, BH and DSBT during P2. Calves were assigned randomly on the following treatment groups, G1: 50% CS + 50% BH, G2: 50% CS + 37.5% BH + 12.5% DSBT, G3: 50% CS + 25% BH + 25% DSBT, G4: 50% CS + 12.5% BH + 37.5% DSBT and G5: 50% CS + 50% DSBT. Results showed that replace of BH by DSBT improved (P<0.05) the digestibility coefficients of DM, OM, CP, CF, EE and NFE as well as nutritive values represented as TDN and DCP during the different experimental periods, where, the G3showed the highest (P<0.05) values. Also, ruminal pH value and ammonia-N were decreased (P<0.05) with G3, however, TVFA's was increased (P<0.05). But, there were no differences among G1 and G2 or G4 and G5. Moreover, the effect of replace of BH by DSBT on plasma total protein, albumin, creatinine, urea-N, liver enzymes (AST and ALT) activity, Cholesterol, Triglycerides and glucose of Friesian calves during different experimental periods were improved with G3 and G2. The values which obtained in this study are with the normal range. Calves in G3 recorded the highest LBW, WG and ADG followed by calves in G2, G1, G4 and G5 during the different periods. Also, G3 and G2 showed the highest total and net revenue compared to other groups. It could be concluded that there place 50% of BH by DSBT (G3) for Friesian calves rations improved the Friesian calves performance and economic efficiency.