The study was designed to elucidate the impact of mannanoligosaccharide (MOS) on the growth performance, weight of lymphoid organs and intestinal histomorphology of broilers during starter phase. A total of 180 day-old broiler chicks were distributed into 3 treatments, designated as MOS-0, MOS-50 and MOS-100 having MOS at the rate of 0, 50 and 100 g/kg respectively. Each treatment was further replicated 3 times having 10 chicks per replicate. Treatment MOS-0 was kept as control and the birds in this treatment were fed on basal ration without alteration in feed contents while the other treatments MOS-50 and MOS-100 represented 50 and 100 g MOS/kg feed, respectively during starter phase. Feed intake, weight gain and feed conversion ratio (FCR) were significantly (P<0.05) high in Treatment MOS-100 compared to the control. Similar trend was also observed in the weight of bursa,thymus and spleen. Significantly higher villus height, crypt depth and goblet cell count was recorded with MOS-100 while values lower with MOS-0 treatment. It was concluded that improvement in growth performance, intestinal histomorphology and relative weight of lymphoid organs in broiler chicks during starter phase was attributed to the supplementation of MOS.