A total of 105 finishing pigs [(Yorkshire × Landrace) × Duroc] with an initial body weight of 51.0 ± 3.33 kg were used in a 10 wk trial to evaluate the effect of a protected blend of organic acids (OAs) and medium-chain fatty acids (MCFAs) in finishing pigs. Pigs were randomly allotted to one of three dietary treatments such as CON (basal diet); MC1 (basal diet + 0.1% protected organic acids); and MC2 (basal diet + 0.2% protected organic acids). Pigs fed the MC1 and MC2 diets increased (P < 0.05) average daily gain and gain to feed ratio compared with the CON diet from weeks 0 to 5 and during the whole experiment. Pigs fed the MC1 and MC2 diets increased (P < 0.05) concentration of immunoglobulin G (IgG) compared with the CON diet at the 5th week. Administration of the MC1 and MC2 diets increased Lactobacillus counts and decreased Escherichia coli counts compared with the CON diet (P < 0.05). However, no significant differences were found on nutrient digestibility, meat quality, and faecal noxious gas emission among treatments. In conclusion, the blend of OAs and MCFAs supplementation increased growth performance, the concentration of IgG, and the Lactobacillus counts, as well as decreased the E. coli counts.