In a fattening experiment lasted 120 day ,fifteen Sudanese camel calves  (Camelus dromedaries)averaged 245 Kg live body weight (LBW) and aged 2-3 years were randomly divided into three similar groups to study the effect of some different feeding regimes on  their  productive performance. Animals were fed individually on concentrate feed mixture (CFM) at 2, 1.5 and 1% of LBW for groups 1, 2 and 3, respectively. Treated rice straw (TRS) with urea (5%) and molasses (10%) was offered ad lib. for all animals to decrease the feeding cost. Feed intake and live body weight were recorded weekly then daily weight gain and feed to gain ratio were calculated. At the end of the experimental period, three animals from each group were used in digestion trail to evaluate   nutrients digestibility, nutritive value and nitrogen balance. The obtained results could be summarized as follows: 1) There were significant decrease in nutrients digestibility and nutritive value (as TDN and DCP) and slight improvement in nitrogen balance was observed for camels fed R2 and R3 compared with R1. 2) There were significant decrease in both concentrate feed mixture (CFM) and total dry matter intake (TDMI) was noticed for camels fed R2 and R3 compared with R1, while, roughage intake (treated rice straw) was increased significantly in R2 and R3. On the other hand, roughage: concentrate ratios were 25:75, 33:67 and 49:51 for R1, R2 and R3, respectively. 3) There were insignificant differences in both daily gain and feed conversion (kg DMI/ kg gain) among the three tested groups, being 668, 635 and 577 g for daily gain and 9.13, 9.18 and 9.10 for feed conversion, respectively. 4) There was   a decrease in feed cost, LE/ kg gain and an increase in economical efficiency were recorded for camels fed R2 and R3 compared with R1. Conclusively, fattening Sudanese camel calves could be fed on concentrate feed mixture at 1% of live body weight plus treated rice straw with urea (5%) and molasses (10%) ad lib. with an improvement on productive performance and economical efficiency.