The present study aims at analyzing effects of mannanoligosaccharide (MOS) and organic acid blend (OAB) supplementation individually and in combination on carcass yield, small intestinal microarchitecture and serum biochemistry in Hubbard chicks. A total of 128 one day-old chicks were divided equally in four different groups with each group having 4 replicates. The number of birds per group were 32 whereas the number of birds per replicate were 8.The first group was kept as control (CONT) whereas, the second (MOSG) and third (OABG) groups were given MOS (2g / kg of feed) and OAB (3g / kg of feed), respectively. The fourth group (MOS+OAB) was given combination of MOS (2g / kg of feed) and OAB (3g / kg of feed). Birds were given ad-libitum feed and water during an experiment of 35 days. At the end of trial, two birds from each replicate were slaughtered for analysis of the selected parameters. The results showed that carcass weight and carcass yield were significantly high (p < 0.05) in MOS+OAB compared to MOSG, OABG and CONT. The results of small intestine microarchitecture showed that villus length, villus width, villus to crypt ratio, villus surface area, acidic, mixed and total goblet cells increased significantly (p < 0.05) in birds that were fed MOS and OAB alone and in combination whereas crypt depth decreased significantly (p < 0.05) after the selected supplementation in all small intestinal segments compared to control group. Level of thyroid stimulating hormone (TSH) was increased significantly (p < 0.05) by the dietary treatments under study individually and in combination. It is concluded that supplementation of MOS and OAB in combination is beneficial compared to their individual effects in broiler chicks.