The experimental work was carried out during the period from February to April 2016 to determine the effects of inclusion Spirulina platensis over the broiler diets on productive performance and some physiological responses. The total number of birds (200 Cobb broiler chickens at seven d of age) were distributed randomly into five treatments (40 chicks each), and each treatment contained four replicates of ten chicks being, a commercial basal diet (control group), while the other groups were supplemented with Spirulina platensis (0.3, 0.5, 0.7, and 0.9 g /kg). The obtained results of the experiment showed that chicks fed with 0.9 and 0.7g/kg of feed Spirulina platensis had significant better valus of LBW, BWG, GR, PI, immune organs, improved FCR, blood parameters, and microbial load. Moreover, chicks fed with 0.7g/kg of Spirulina platensis had the best economic efficiency. Generally, it could be concluded that, dietary with 0.7and 0.9 g/kg of feed Spirulina platensis could improve the growth performance, blood parameters, biochemical changes in serum and microbial load. From an economical point of view, supplementation of 0.7g/kg of Spirulina platensis is recommended of cobb chicks.