A study was carried out for a period of four months using eighteen weaned White Giant broiler rabbits of four to six weeks age to find out the effect of dietary supplementation of prebiotic mannan oligosaccharides (MOS) on growth performance and carcass characteristics. The rabbits were divided into three groups of six animals each. The animals were randomly alloted to three dietary treatments, T1 (control diet as per NRC 1977), T2 (control diet + 1.5 g MOS per kg diet) and T3 (control diet + 3 g MOS per kg diet) using completely randomized block design. The data on fortnightly body weight, average daily dry matter intake, average daily gain, feed conversion efficiency, serum parameters (Ca, P, total protein, plasma cholesterol and HDL cholesterol ), carcass characteristics ( dressing per cent, meat to bone ratio and weight of internal organs) and caecal microbial count (TVC and coliform) were used for evaluation of the work. The cost of production per kg body weight gain was also calculated. The results of the study indicate that all the three dietary treatments were similar (P> 0.05) in various factors such as fortnightly body weight, average daily gain, average daily DM intake, haematological parameters, carcass traits and feed cost per kg body weight gain. However the rabbits supplemented with MOS at 1.5g and 3g per kg diet obtained the better Ca availability (P< 0.01) and weight of heart was highest for T3 diet and weight of spleen was greater for both T2 and T3 diet. The animals fed diet supplemented with prebiotic, Bio-Mos showed reduced incidences of diarrhoea and resulted in better intestinal integrity leading to a protective effect against common pathogens. The T3 ration supplemented group obtained significant reduction of coliform count in caecal content and had longer ileal villi indicating better absorption and better resistance. From the overall results it can be concluded that the MOS supplementation at 3g per kg diet had better absorptive power and disease resistance and thus can be used as feed additive in rabbits where high weaning stress and digestive disorders are common.