Two experiments were conducted to study the effects of chito-oligosaccharides (COS) on pig’s performance and immune response. In Experiment 1, a total of 117 Landrace × Yorkshire × Duroc pigs (with average body weight of 30.7±1.56 kg) were allocated to three treatments based on body weight to evaluate the effect of COS on growth performance, nutrient digestibility and pork quality. Treatments were control (no COS), T1 [0.04% COS for grower (30-55 kg), 0.02% for early finisher (55-85 kg) and 0.02% for late finisher (85-110 kg)], and T2 [0.1% COS for grower (30-55 kg), 0.05% for early finisher (55-85 kg) and 0.025% for late finisher (85-110 kg)], respectively. Each treatment had 3 replications with 13 pigs per replicate. At the end of feeding trial, 2 pigs per replicate (6 per treatment) were slaughtered for carcass analysis and pork quality evaluation. During the overall period (30-110kg), the growth performance and apparent nutrient digestibility were not affected (P>0.05) by dietary treatments. However, FCR was improved by 5.9% in T2 group when compared with control. Dressing percentage, backfat thickness, pork colour and marbling score were not influenced by the addition of COS. With the increase of storage time, TBARS was decreased and drip loss, pork colour were improved by the addition of COS. Linear reduction (P<0.10) in the LDL content of pork with the addition of COS was noted. In Experiment 2, fifty-four Landrace × Yorkshire × Duroc pigs (with average body weight of 30.9±1.78 kg) were penned (6 pigs per pen, 3 pens per treatment) and allocated to three treatment diets for immune response study. The diets fed were: 0% COS (control), 0.1% COS (T1) and 0.3% COS (T2). During the 70-d study, 3 pigs per replicate were vaccinated with Actinobacillus pleuropneumoniae and Pasteurella multocida and the antibody titers were measured at d 0, 5, 30, 50 and 70. Higher (P<0.05) antibody titers were observed for both of the COS added diets when compared with control. Flow cytometry was used to determine porcine lymphocyte subpopulations at 28^th and 54^th day from the other 3 unvaccinated pigs of each replicate. There was a quadratic increase (P<0.10) in MHC class-II and B-cells at 54^th day in pigs fed COS diets. In conclusion, feeding chito-oligosaccharides in growing-finishing pigs improved pork stability and reduced cholesterol in pork without affecting growth performance, and the immune response was improved by chito-oligosaccharides supplementation.