The point of this examination was to research the impacts of dietary supplementation with rosemary extract 1g/kg diet and synthesized calcium nanoparticles with rosemary extract (0.5 and 1 g/kg) on growth performance, blood profiles and histology in broilers. A total of one hundred twelve1-d-old unsexed broiler chicks were randomly allotted to 4 treatments with 4 replications per treatment and 28 chicks per pen floor. Rosemary extract at 1 g/kg diet, nano rosemary (0.5 and 1.0g/kg) were significant of Body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) as compared to control group in the starter period. On the other hand, no significant differences were observed among the control group, rosemary extract and nano-rosemary (0.5 and 1 g/kg diet) groups in feed intake and feed conversion ratio during the whole experimental period. Dietary supplementation with rosemary extract (1 g/kg diet), or rosemary (0.5 and 1 g/kg diet) did not significantly affect the plasma levels of glucose, total protein, albumin and high-density lipoprotein (HDL). But, the supplemented groups with rosemary extract and nano- rosemary 0.5 g/kg had slightly higher concentrations of HDL compared with other groups.  However, dietary supplementation with rosemary extract and nano-rosemary  led to a significant reduction in plasma low-density lipoprotein (LDL) concentrations compared with the control group. The results related for humoral immune response of broiler chickens showed significant increases in immunoglobulins in the treated groups compared with the control group. The rosemary extract and Nano-rosemary (0.5 and 1.0 g/kg), applied in the present study, significantly increased total antioxidant capacity (TAC) in the treated broiler chickens as compared to the control group. In a similar way, malondialdehyde (MDA) was significantly lower in broiler chickens received the rosemary extract containing diets compared with the control group.The present outcomes show that supplemental nano rosemary of diet has a beneficial effect on lipid profile, immunity, antioxidant status and histological observations of broiler chicken.