This study was conducted to investigate the effects of prebiotic and organic zinc alone and in combination in broiler diets on the live weight gain (LWG), feed consumption (FC), feed consumption ratio (FCR), carcass yield, some relative organ weights and blood parameters. A total of 160 Ross 308 one-day old male chicks were assigned to 4 treatment groups with 4 replicates of 10 birds each. Treatment for each group consisted of: first group (control group) received basal diet without supplementation; second group received 1 g/kg Mannanoligosaccharide (MOS); third group received 80 mg/kg organic zinc (OZn); and fourth group received 80 mg/kg organic zinc + 1 g/kg Mannanoligosaccharide (MOS+OZn). The study lasted 42 days. The supplementation of MOS and OZn had no effect on the LWG, FC, FCR, carcass yield, serum aspartate aminotranferase, (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and triglyceride levels during the experiment (P>0.05). Relative organ weights (liver, spleen, pancreas) were significantly higher in OZn group than those in the other groups (P<0.001). There was a significant difference in serum total cholesterol and glucose levels between treatment groups and control group (P<0.001). Serum Zn and Fe levels were significantly lower in control group than those in OZn and MOS+OZn groups (P<0.001). The highest and the lowest Cu levels were in the MOS+OZn and control groups, respectively (P<0.001). These data suggest that OZn with MOS combination may have a beneficial effect on serum mineral level in broilers.