This study aimed to investigate the effects of L-carnitine (LC) on productive performance, carcass composition, blood parameters as well as the lipid metabolism, immune response and antioxidative properties of broiler chicks from day 7 to 35 of age. A total of 280 unsexed Cobb chicks were assigned equally into four treatment groups. The first group fed a basal diet (control), while the other three groups were fed basal diet supplemented with 50, 100 and 150 mg of LC/ kg diet. Supplementation of LC to diets significantly increased BW, BWG, decreased FI and improved FCR, economical efficiency and production index. Where, Chicks fed basal diet supplemented with 50 mg of LC had significantly higher final BW and BWG, lower FI and better values of FCR, economical efficiency and production index followed by those fed basal diet supplemented with 100 and 150 mg LC compared to the control group. Treated groups significantly decreased serum urea, creatinine, alanine amino transferase (ALT), aspartate amino transferase (AST), total lipids, triglycerides, cholesterol and low-density lipoprotein (LDL) while increased glucose, high-density lipoprotein (HDL), total protein, total antioxidant capacity (TAC), superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione (GSH), triiodothyronine (T3), thyroxine (T4), hemoglobin, packed cell volume (PCV), red blood cell (RBC's), white blood cell (WBC's), lymphocyte, globulin, α -globulin, globulin -β and globulin-γ, immunoglobulins (IgG, IgM and IgA), bactriocide activity (BA), lymphocyte transformation test (LTT), phagocytic activity (PA) and index (PI) compared to control group. Feeding diet with LC significantly increased carcass dressing and total edible parts and decreased abdominal fat compared to the control. In conclusion: L- carnitine supplementation to broiler diets improved productive performance, economical efficiency, immune response and antioxidative properties of broiler.