The purpose of this research was to study the addition of cinnamon powder in diet, on productive performance, blood metabolites and inner organs weight of broiler chickens. Therefore, an experiment was carried out with two hundred and twenty five male broiler chicks Ross 308 in form of a completely randomized design with 5 treatments and three replicates during 42 days. Treatments were involving: 1- control group (basal diet without any additive), 2- basal diet plus 0.1 % cinnamon powder, 3- basal diet plus 0.2 % cinnamon powder, 4- basal diet plus 0.3 % cinnamon powder, 5- basal diet plus 0.5 % cinnamon powder. The results of this research showed that cinnamon powder has no significant effect on the blood cholesterol, triglyceride and caecum levels plus percentage of pancreas weight (P>0.05). Whereas, addition of cinnamon powder induced significant effects on the glucose, LDL, AST, ALT, TBA and some of the inner organs weight percent such as liver and abdominal fat (P<0.05). According to the results, the highest TBA number was related to control treatment and the lowest was also related to treatment 4. Moreover, the highest and the lowest glucose level were belong to 0.5 % and control groups respectively, and the highest LDL and AST levels and the lowest ALT levels were also belong to 0.3 % cinnamon powder treatment. Furthermore, according to addition of this medicine herb into diet was affected the broilers performance from 1 to 42 days old (P<0.05), so that, at 42 days old the highest feed conversion ratio and the lowest weight gain were related to 0.5 % treatment. In respecting on the 42 days, the broilers performance was decreased through additive received groups than control group, as a result addition of cinnamon powder in aforementioned levels should be have caution in broiler chicks.