The aim of this study was to investigate the effects of dietary supplementation with three levels of thyme (5, 10 and 15 g/kg) and its essential oils (0.5, 1.0 and 1.5 g/kg) on growth performance, blood profiles, immune response and antioxidant status  in broiler chickens. A total of one hundred-forty day-old unsexed broiler chicks were randomly allotted to 7  equal groups, each with 4 replicates, and kept in battery cages. Feed and water were offered ad libitum till the termination of the trial at 6 weeks of age. Growth performance and blood parameters were measured. The control group and the group fed 5 g/kg thyme were significantly better in their LBW and BWG as compared to other groups in the first three weeks of study and whole experimental period. On the other hand, feeding the diet having 5 g/kg thyme enhanced feed intake during the starter and whole experimental periods as compared to other groups. Broilers fed the diet fortified with1.0 g/kg thyme oil  displayed significantly better feed conversion ratio than did other experimmintal groups during the starter and whole experimintal periods. Dietary treatments had no significant effect on the plasma levels of total lipids, triglycerides and total protein as well as activity of AST and ALT. It was observed that broiler chickens fed the diets conaining thyme and/or essential oils exhibited higher concentration of plasma HDL compared with the control group, with the highest concentration of HDL in 15 g/kg thyme-group. On the other hand, dietary supplementation with thyme or its essential oils led to a significant reduction in plasma LDL compared with control group. The humoral immune response was improved in broiler chickens fed the treated diets as evidenced by a significant increase in immunoglobulins (IgG, IgA and IgM) compared with the control group. It is of great interest to notice that thyme and its essential oils administred-groups significantly increased TAC but decreased MDA as compared to the control group. Findings from this study highlighted the beneficial effect of thyme supplementation in diets at the rate of 5.0 g/kg on cholesterol , immunity and antioxidant status of broiler chickens