This study was conducted in one of the commercial poultry farms for study the effect of dietary supplementation of coriander (Coriandrum sativum L) and Fennel (Foeniculum vulgares) seed powder and their mixture in improvement the production and physiological performance of broiler. In this experiment we used 120 chick of Hubbard at one day old and distributed randomly to four treatments with three replicates for each treatment and was given two types of diets, The first is starter that have been feeding from the 1-22 day age old and finisher that have been feeding from 23-45 day age old. The control group included the chicks that feeding on the basal diet without any additive.T1 which included the group of chicks that feeding on the basal diet plus 5% of coriander seed powder, While T2 included the group of chicks that feeding on the basal diet plus 5% of fennel seed powder then T3which included the group of chicks that feeding on the basal diet plus the mixture of 2.5% of coriander seed powder and 2.5 % of fennel seed powder. The results showed the present of a significant effect (p<0.05) of adding coriander and fennel seed powder and their mixture in the broiler diet in the body weight, weight gain ,feed conversion ratio, feed intake ,carcass and internal organs weight compared with the control group as well as the results showed no significant difference (p>0.05) in dressing percentage, heart weight and serum protein concentration between different treatments ,while we saw a significant decrease (P<0.05) in concentration of glucose, cholesterol, triglycerides and uric acid in blood serum of treatments compared to the control group. In this study, we conclude that the dietary supplementation of coriander and fennel seed powder and their mixture lead to improve the production and physiological performance of broiler.