This research was carried out to investigate the effects of Nano-silver (Ag-NPs) on traits of productivity, oxidative stress state and some of blood Parameters in broiler chicks. A total of 240, one-day-old male broiler chicks (Ross 308) were allocated in a completely randomized design into four groups containing 60 birds, four replicates and 15 birds in each experimental pen. Basal diet supplemented with different levels of Ag-NPs (Diameter 14 +/- 0.8 nm) was given throughout research (1-42 days). Experimental diets included: 0 (Control), 20, 40, and 60 ppm Ag-NPs/kg diet. At the end of study period, one bird with closest weight to the mean of any treatment was selected. Blood samples were collected, centrifuged and removed serum stored at -20 degrees C until analysis. Then birds slaughtered and spleen, thymus, and bursa of Fabricius removed and their relative weights calculated. The results showed that nano-silver has no significant effect on growth performance but a decrease was found in feed efficiency. Relative bursa weight had significantly decreased in compared with control treatment (P<0.05). Lowest weight among treatments observed in treatment that supplemented with 60 ppm nano-silver. Ag-NPs had significantly effected on oxidative stress enzymes activity among treatment in comparison to control group (P<0.01). Blood parameters such as ALT, AST, ALP, TP, Albumin, Gama globulin, triglyceride, and cholesterol were significantly affected by using nano-silver in broiler chicks (P<0.05). (C) 2011 PVJ. All rights reserved