Abstract: This study was carried out to investigate the effects of Medicago sativa seeds as isoflavones (ISF) source on some productive and physiological parameters of broiler chickens. One hundred and twenty day-old Hubbard commercial broiler chicks were randomly divided into 4 experimental groups of 30 chicks each. Groups 2, 3 and 4 were given a diet containing 0.25, 0.5 and 1.0% of Medicago sativa seeds while group one served as a control group. Results revealed that live body weight, body weight gain and carcass weight showed a non-significant increase of Medicago sativa seeds groups compared to the control group and the 0.5% treated group had the highest mean. As well, all levels of Medicago sativa seeds recorded gradually and significantly increased (p≤0.01) in feed consumption and that was dose-dependent, whereas, these treatments did not revealed an improvement in feed conversion compared to the control group which had the lowest feed conversion mean. Blood biochemical analysis showed that plasma total protein and albumin concentration were gradually increased in the treated groups compared to the control group but without significant effect, while, plasma total lipids and cholesterol concentrations were gradually and significantly decreased in treated groups compared to the control. Plasma glucose concentration was increased in Medicago sativa seeds groups but the significant was with 0.5% treatment only. Medicago sativa seeds resulted in decrease the AST and ALT enzymes activities in treated groups and this effect was non-significant. Similarity, lipid peroxidation activity (Malondialdehyde) was significantly decreased due to treated chicks with Medicago sativa seeds and this effect was dose-dependent. It could be concluded that Medicago sativa seeds has some physiological effects on broiler chicks that feed on Medicago sativa inclusion diet.