The present work aimed to investigate the effect of dietary protein level on the degradability of some feeds two rich in protein (SBM, UDCSC) and the other two rich in energy content (barley and corn). Six adult Rahmany sheep were used in the present work, three males for digestibility and nitrogen balance trials and three females fitted with rumen permanent fistulae for in sacco study. Animals were fed three experimental diets based on, 40% rice straw as a roughage and containing 60% concentrate mixture with different protein levels (14.55,16.66 and19.28%) crude protein .                 Results could be summarized as follow:  Regarding the differences due to diets no significant difference was detected among diets for crude protein and NFE digestibility, where the values ranged between (66.52±3.19 and 63.89±2.13) for crude protein and between (72.24±3.13 and 70.34±1.84) for NFE. A significant difference was detected among diets for both EE and crude fiber digestibility. Values ranged between (71.49±2.82 and 66.56±3.83) for EE and between (45.25±4.08 and 50.04±3.56) for crude fiber, respectively  (p < 0.05). No significant difference was detected among diets for the total digestible nutrients TDN values, where the highest value was 61.00±1.55 %, and the lowest value was 60.77±1.79 %, while a significant difference was detected among diets for digestible crude protein (DCP) and nitrogen balance (NB) where the highest value recorded was 12.83±1.23 and the lowest value was 9.29±1.13 for DCP, the highest value obtained for (NB) was 3.48±1.06 and the lowest value was 1.62± 0.76 expressed as g/h/day (p < 0.05). Rumen pH did not show any significant difference before feeding and 2,4 and 6 post feeding while a significant difference was observed at 8 and 12 hours after feeding. The effective degradability ED values obtained for dry matter and protein show significant differences among diets. The highest value obtained for dry matter degradability DM and crude protein degradability of barley was recorded with diet 1 (60.71± 0.76, 66.09±0.16) and the lowest value was recorded with diet 3 (56.12±0.45) for DM and 60.08±0.03) for crude protein degradability with diet 2 respectively (p < 0.05). For corn dry matter and protein degradability the highest value was recorded with diet 1 (38.49±0.38 and 44.45±0.27) and the lowest value was recorded with diet 3 (35.97±0.40 and 42.13±0.32) respectively (p < 0.05). The ED value obtained for cotton seed cake dry matter and protein degradability showed a significant difference with protein level where the highest value was recorded with diet 1 for both DM and protein degradability (50.41±0.17 and 47.93±0.96) and the lowest value was recorded with diet 3 (45.43±0.29 and 43.52±0.30) (P< 0.05). The ED values obtained for dry matter and protein degradability of soy bean meal SBM showed a significant difference with protein level where the highest value recorded was with diet 1 (65.87±0.51 and 64.94±0.74) and the lowest value was recorded with diet 3 (59.34±1.33 and 61.05±0.47) for DM and protein respectively (p < 0.05). In conclusion the level of protein affect significantly the ED value under the present experimental condition and this effect could be detected with higher level of protein while medium and low levels did not show a significant difference.