The protected organic acids consist of medium chain fatty acid (MCFA) for animal nutrition and metabolism made by technology of Joint Matrix coating (JMT). The objective of the present study was to evaluate the effect of protected organic acid supplementation in piglets particularly at the weaning. A total of 112 weanling pigs with an average BW of 6.70 ± 1.31 kg were allotted to 4 experimental diets as: CON (basal diet); OA1 (CON + unprotected organic acid 0.2%); OA2, (CON + protected organic acid 0.1%) and OA3 (CON + protected organic acid 0.2%). There are 7 replications/treatment and 4 pigs/replication. The organic acid such as 17% fumaric acid, 13% citric acid, and 1.2% medium chain fatty acid (capric and caprilic acid) were used in the present experiment. Effects of treatments (Control, OA1, OA2, OA3) were analyzed by ANOVA as a randomized complete block design. Results are presented as least squares means and the variability in data was expressed as standard error (SE). The probability values less than 0.05 were considered as significant. Average daily gain (ADG), average daily feed intake (ADFI), gain to feed ratio (G:F), apparent total-tract digestibility (ATTD) were determined along with WBC, RBC, lymphocytes, IgG, Lactobacillus and Escherichia coli (E. coli). Average daily gain (ADG) at 0–2 wks were increased linearly (CON:307 g, OA1: 311 g, OA2: 319 g, OA3: 324 g) ADFI at 2–6 weeks (CON:762 g, OA1:757 g, OA2:755 g, OA3:750 g) and the overall ADFI was increased. A linear increasing effect was shown in the ATTD of dry matter (DM) (CON: 80.40%; OA1: 80.24%; OA2: 82.87%; OA3: 83.11%) with OA2 and OA3 treatments, the serum IgG in OA2 (235 mg/dL) and OA3 (245 mg/dL) treatments and the lymphocyte in OA3 treatments (50.9%) and in supplementation coated protected organic acid of Lactobacillus. However, a linearly reduced effect was observed in the population of E. coli (CON: 5.70, OA1: 5.65, OA2: 5.60, OA3: 5.49). In conclusion, dietary protected organic acids improve health status and performance in weanling pigs.