Distillers dried grains with solubles (DDGS) is a by-product from processing corn to produce bio-ethanol, and it contains almost three times higher protein, fat, and fiber than corn. Intake of higher amount of nutrients originated from corn in lactating sows may contribute to changes in milk composition and thus alter the growth of suckling piglets. Therefore, the objective of this study was to evaluate effect of supplementing DDGS in the diet of lactating sows on variation in the body weight of piglets. A total of 50 sows with parities of 3 to 5 were usedand allottedinto one of four treatments which included 0 (CON), 10% (DDGS10), 20% (DDGS20), or 30% (DDGS30) DDGS in the diet. Diets were fed to sows during the whole lactation period. Individual body weights of piglets were measured within 24 h after farrowing and at weaning. No significant differences were observed inthe coefficient of variation (CV) for body weight of piglets within a litter after farrowing and at weaning among the treatments (p>0.05). There was, however, a tendency of decreases in the CV for body weight of piglets within a litter at weaning compared with that after farrowingin the DDGS10 and DDGS20 treatments. At weaning, the percentage of the number of piglets weighing less than 4.5 kg in DDGS20 (4.86%, 7 out of 144; p<0.05) or DDGS30 (5.04%, 6 out of 119; p=0.059) was lower than that in CON (12.41%; 17 out of 137) although this pattern was not observed in DDGS10. In conclusion, addition of DDGS in lactating sow diets improved piglet performance by reducing the number piglets weighing less than 4.5 kg.