Three females Barki sheep with an average body of weight 45 kg were used in this study in order to evaluate the degradability of dry matter (DM), organic matter (OM) and crude protein (CP) of four protein sources. Four mixed diets supplemented with one of four protein sources; soybean meal (SBM), linseed meal (LSM) undecorticated cotton seed cake(UDCSC)   or  urea as protein sources., Meat and bone meal (MBM) was added to all diet The degradability of whole diet was also studied. .  Roughage: concentrate ratio was 1:1 for all diets which were almost iso-caloric and iso nitrogenous. .Data could be summarized as follow 1-The dry matter degradability of sources ranged between 41.47±0.28 for MBM and 60.39±0.47 for SBM.Significant differences were found (p < 0.05). 2- The organic matter degradability of protein sources ranged between33.47±0.46 for UDCSC and 58.72±0.34 for SBM.  Significant differences were found. (p < 0.05). 3- The crude protein degradability of protein sources ranged between46.45±0.38 for MBM and 59.37±0.41 for SBM. Significant differences were found (p < 0.05). 4- The dry matter degradability of the whole diet ranged between 41.09±0.23 for UDCSC and 49.17 ±0.39 for SBM. Significant differences were found (p < 0.05). 5- The organic matter degradability of the whole diet ranged between 39.13±0.44 for UDCSC and 46.40±0.67 for SBM with significant differences (p < 0.05). 6-- The crude protein degradability of the whole diet ranged between40.66±0.25 for UDCSC and 60.43±0.16 for MBM with significant differences (p < 0.05).