In order to find out the proper level of coriander seed powder (CSP) supplementation on the growth perfomance of Cobb500 broilers, an experiment was carried out on a total of 450 Cobb500 broilers at 8 days old which were randomly designed into five dietary treatments as followed as: control including a basic diet without additional coriander seed powder, and other four levels of CSP at 0.5, 1, 1.5 and 2 g/kg feed named as CSP_0.5, CSP_1.0, CSP_1.5, and CSP_2.0, respectively. There were three replicates with 30 chicks per each. The results showed that supplemention of  CSP significantly reduced the infection rate of CRD from 5.56 to 8.89% compared to control (13.33%). The body weight of chicks were significant difference among treatments at 14, 21, 35 and 42 days old, CSP_2.0had the highest final weight (2,675.6 g/bird) and lowest was on control (2,484.4 g/bird). The daily weight gain and feed conversion ratio were statistically significant difference at 14 and 21 days old