The current work was conducted to investigate the effect of dietary leftover food inclusion on growth performance, carcass traits and some blood biochemical parameters of Muscovy ducks. Thirty six (36) two-week old ducks (average weight 393.2 g) were obtained from local commercial source and randomly distributed into 4 groups (9ducks/each). In the first group, ducklings were fed ad-libitum on grower-finisher control diet (diet 1), while birds in the second, third and fourth groups fed on diets containing 10%, 20% and 30% leftover food, respectively (diets 2, 3, 4). The experimental diets were formulated in a mash form (yellow corn, soybean meal, wheat bran and sunflower oil) to meet the minimum nutrient requirements cited by NRC (1994) for ducks. Ducklings were fed according to one phase feeding program (grower- finisher, 14- 70 days). Growth performance, carcass traits and some blood biochemical parameters were assessed. The results showed that, ducks fed on diets containing 10, 20, 30% leftover food achieved significantly (p < 0.05) higher body weight gain (3084.2±30.3, 3141.5±30.8, 3169.0±29.1 g), respectively compared with the control (2945.2±22.3g) with lower feed intake. Highest weight gain averages with best feed conversion (3.22, 3.14, and 3.11) respectively compared with the control. The highest dressing percentage was recorded in ducks fed on diet containing 30% leftover food (79.3%), while the lowest was observed in control group (75.6%). Addition of leftover food to duck diets had no significant effect (p < 0.05) on the weights of internal organ. Total serum protein, albumin and globulin values were decreased significantly (p < 0.05) by increasing the level of dietary leftover food. Inclusion of leftover food to duck diets increase significantly (p < 0.05) triglycerides and had no significant effect on serum cholesterol. Results of the current study concluded that, the best growth performance and economical feed efficiency was observed in ducks fed on diet containing 30% leftover food which surpassing all treated groups and achieved the best body weight gain.