The experiment was conducted in the rabbit's farm belonging to Environmental Studies and Research Institute, University Sadat City, Menoufia Governorate, Egypt. This study aimed to investigate the effect of supplementing green algae (Pediastrum spp) and natural antioxidants (Senecio glaucus) in the form of powder or extract on the growth performance of New Zealand white rabbits aged 4 weeks with an average weight of approximately 600 gram.A number of 36 rabbits were used in this experiment, divided randomly into six groups, each group consisting of 6 rabbits. The first group (D1) was fed on commercial diet 17% protein (positive control), the second group (D2) was fed on a basic diet 14% protein (control negative), the third and fourth groups (D3 and D4) were fed on a basic diet supplemented with Pediastrum algae in the form of extract and powder and the fifth and sixth groups (D5 and D6) were fed Senecio glaucus in the form of extract and powder. The experiment lasted 10 weeks period. The obtained results showed that the addition 10g of Pediastrum powder /kg of feed to growing rabbits led to a significant increase in the growth performance (final body weight, daily weight gain, feed conversion ratio and performance index), followed by those fed D6 diet (Basal diet + 10 g of Senecio glaucus powder /kg feed.), while rabbits fed the D5 diet (Basal diet + 10 ml of Senecio glaucus extract /kg feed) had the lowest feed consumption. In general, there was an improvement in some characteristics of the carcass, blood and microbial activity in the cecum in the groups D4 and D6. There was also an improvement in the economic efficiency by adding Pediastrum and Senecio glaucus compared to the control groups.