This experiment was designed to investigate the biological and economical response of feeding effective microorganisms treated wheat bran provided at different level to young crossbred calves. Twenty crossbred Frisian*Boran calves weighing (100± 10.85) kg and 6 months of age were selected and divided randomly in to 4 similar treatment groups (5 animals each group) in 100 days feeding trial. All the calves in the different groups were fed similar basal diet of native pasture hay. The first group (T1, control) fed native hay as a basal diet and concentrate mixture as a supplement. Group 2, 3 and 4 (T2, T3 and T4) fed the same basal diet and concentrate mixture replaced by 33, 66 and 100 % EM treated wheat bran, respectively.