The objective of the present investigation was to study the effect of two supplemented algae on nutritive value of lactating Damascus goats rations and its effect on performance of kids, milk production, milk composition, digestion coefficients, feed intake and feed conversion. Twenty seven Damascus lactating   goats of 2-4 years old and average live body weight of 48.5±1.4kg were chosen divided and into three  similar groups (9 animals each) R1 (control), R2 and R3. The groups were assigned at random to receive one of the three experimental rations. Animals of group R1 were fed 50% concentrate feed mixture (CFM) + 30% berseem hay + 20% wheat straw (control), R2 were fed 50% CFM + 30% berseem hay + 20% wheat straw with supplemented algae (Spirulina) and R3 were fed 50% CFM + 30%berseem hay + 20% wheat straw with supplemented algae (Ulva rigida) 0.2% of feed intake.  At the end of the trial, three digestibility trials were conducted to determine digestibility coefficients and nutritive value of experimental rations. In addition, rumen liquor and blood samples were taken to determine some parameters.  All supplemented in the present study decreased (P<0.05) CF, ash, ADL and hemicelluloses, but CP content had increased. The results revealed that the algae supplementation recorded highest digestibility coefficients (P<0.05) for all nutrients fiber fractions and nutritive value of R2 (P<0.05) compared with control. Nutrients digestibility coefficients, concentrations of ruminal ammonia nitrogen and total volatile were significantly (P<0.05) higher, which ruminal pH values were significantly (P<0.05) lower for rams fed algae supplemented diets than control at the sampling times 4 hrs. The highest body weight was recorded with R2. The algae supplemented recorded better feed conversion (DMI/daily milk yield) for R2and R3, respectively compared with the control (R1). It could be concluded that supplemented goats ration with algae tended to increase digestibility coefficients and nutritive values, increased milk yield and improved feed conversion as kg DM intake per kg milk yield.