Abstract: This study aimed to determine the effects of dietary supplementation with combined arginine and glutamine on growth performance and intestinal development in neonatal piglets. The piglets (n = 144, 4 days old) were assigned randomly to receive one of four diets for 21 days: basal diet (control diet) or the basal diet supplemented with either 0.6% Arginine (Arg diet), 1.0% Glutamine (Gln diet) or both 0.6% arginine and 1.0% Glutamine (Arg/Gln diet). The results showed that Arg/Gln diet increased average daily gain and average daily feed intake compared with both control and Gln diets (p<0.05). Concentrations of serum T3 and insulin were greater for the Arg/Gln diet than the control diet (p<0.05). The Arg/Gln diet increased the duodenal villus height compared with the other three diets (p<0.05). In the jejunal mucosa, the Arg/Gln diet increased the glutathione peroxidase and catalase activities compared with the control diet (p<0.05). The Arg/Gln diet also increased the sucrase activity compared with both control and Arg diets (p<0.05). These results suggested that dietary supplementation with combined arginine and glutamine could improve small intestinal morphology and anti-oxidants and digestive capabilities and could be beneficial in growth performance and gut maturation of neonatal piglets.