This study was conducted to evaluate the effects of non-specific immuno-stimulator(NIS) supplementation on growth performance and carcass characteristics in finishing pigs. A total of eighty [Duroc×Yorkshir×Landrace] pig(60.55±3.72 kg in average initial body weight) were used for a 9-week assay. Dietary treatments included as follows 1) CON(basal diet), 2) NISI(basal diet for 6 weeks and 0.05% NIS for 3 weeks). 3) NIS2(basal diet for 3 weeks and 0.05% NIS for 6 weeks) and 4) NIS3(0.05% NIS for 9 weeks). Average daily gain during the feeding period was not significantly different among the treatments (p>0.05). However, average daily feed intake was higher in NIS2 than CON(p0.05), The appearance rate of A or B carcass grade was much higher in NISI (58%) and NIS3 than CON(50%) and NIS2(50%). L^(*)(lightness) value of loin was higher in NISI and NIS3 than CON and NIS2. However, there was no effect by dietary NIS(p>0.05). Although a^(*)(redness) value of loin was lower in CON than other treatments, there was no significant difference among the treatments(p>0.05). No remarkable differences were found in sensory properties(marbling, firmness and color) among the treatments. The results from the present study suggest that NIS could be an effective feed additive to improve pork quality. However, further research in needed to investigate effect of carcass characteristics.