One hundred and fifty one-day old  Japanese quail chicks were used in this study. Birds were classified into equal five groups (each of 30 birds). During the first week, all quail chicks were fed on the same diet, thereafter chicks were distributed into five groups. Four different levels of coriander seed were added to a standard diet to generate other four groups (0.3,0.6,0.9 and 1.2%) for G₁, G₂, G₃ and G₄ respectively, while G₅ used as control . At the end of experiment (42 days), 5 quails from each group were randomly chosen and slaughtered. Plasma samples were collected and frozen until biochemical analysis. Growth performance and carcass traits were also evaluated. Results obtained could be summarized as follow: 1- Body weight, body weight gain and feed efficiency were significantly differed (P£0.05) and improved by supplementation of coriander seed as compared to control, (4.6, 4.9, -13.1% resp.). 2-  No significant differences were found between the experimental groups for the carcass traits, but heart, liver and kidney were slight increased by the supplementation 0.6, 0.9 and 1.2% of coriander. 3- Plasma total cholesterol, and total lipids were not significantly different than the control, although birds that fed on 0.6 of coriander showed a lesser plasma total lipids than the other treatments. 4- Plasma ALT  activity showed a slight significant differences for quails fed the coriander seeds than the control, but plasma AST activity was not affected. 5- Plasma total protein concentration and H/L ratio were not significantly different by coriander supplementation. 6- Hematocrit showed significantly differences between treatments especially at 0.9 and 1.2% of coriander supplementation. 7- Birds fed  on 0.6, 0.9 1.2% of coriander had the lowest counts of bacteria, (-6.9, -7.6, -58.5% resp.). Therefore, the supplementation of coriander seeds in bird's diets could be recommended to improve the absorption of nutrients in addition to their protective role against the deleterious effects of certain diseases.