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 15 th 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: