The present work was conducted to study the effect of replacement corn silage (CS) by duckweed silage (DS) improved the performance of growing Barki lambs using one of the following rations: R1: 2% of body weights (BW) concentrate feed mixture (CFM) + CS (control), R2: 1.5% of BW (CFM + DS), R3: 1.75% of BW( CFM + DS) and R4: 2% of BW (CFM + DS). Results showed the silages had good smell and were free from any signs of molds in all groups. Digestibility trial was conducted using twelve mature local Barki breed were divided four groups (3 animals each) and were determined digestibility coefficients. Animals in group R3 recorded (P<0.05) the highest digestibility coefficients for all nutrients and nutritive value than others. These results showed a significant improvement (P<0.05) in digestibility coefficients of NDF, ADF and cellulose in R3 than other groups. Results showed insignificant differences (P>0.05) among the three tested groups treatment in all blood parameters. The second experimental trials were twenty Barki lambs with average body weight of 20.00 ± 2.0 kg /head were used. Lambs were divided into four groups (5 animals each) and fed the four respective rations with the same regime of feeding the experimental lasted for month. R3 recorded the highest value of average daily gain compared with R4, R1 and R2. Also, R3 recorded the best value of feed conversion (g DM/g gain) were (4.43) followed by the R2 (4.76), followed by R1 (5.51) than R4(5.65). It was concluded that replacing corn silage by duckweed silage to rations of growing Barki lambs could improve their performance, digestibility, average daily gain and feed conversion. However, for improved performance of the lambs and economic benefits (R3) is recommended.