Objective: The study was conducted to investigate the impact of boron supplementation on nutrient digestibility, inflammatory responses, blood metabolites and diarrhea index, and their relevance to growth performance in weaned pigs housed in good and poor sanitary environments for 14 days after weaning. Methods: A total of 108 male pigs (Duroc * [Yorkshire * Landrace]) weaned at 21 days of age were used in a randomized complete block design with 2 * 3 factorial arrangement. Pigs were assigned to three boron treatments (0, 5, and 10 mg/kg) under two environments (good and poor sanitary) to give six replicates per treatment (3 pigs per replicate). On 0, 7, and 14 days, one pig per replicate was euthanized to collect, ileum tissue samples, and rectal fecal samples. Results: Boron supplementation quadratically influenced (p Conclusion: Pigs offered 5 mg/kg of boron increased weight gain which may be deduced by improved dry matter, crude protein, and energy digestibility regardless of the sanitary conditions. Keywords: Boron; Diarrhea Index; Pigs; Protein Digestibility