Pigs with intrauterine growth restriction (IUGR) represent 20–25% of all pigs born and are culled on farm, resulting in enormous losses. This study tested the hypothesis that dietary supplementation with glycine enhanced the growth of IUGR pigs after weaning. Healthy pigs [14 IUGR pigs (birth weight = 0.98±0.03 kg, mean ± SEM) and 20 NBW pigs (birth weight = 1.44±0.02 kg, mean ± SEM)] were used for the trial. At weaning (21 d of age), pigs within each birth weight group were assigned randomly into corn- and soybean meal-based diets supplemented with 1% glycine plus 0.19% corn starch or 1.19% alanine (isonitrogenous control). There were 7 IUGR pigs and 10 NBW pigs per subgroup. Crude protein content in basal diets was 20% between d 21 and 64, 18% between d 65 and 108, and 16% between d 109 and 120 of age. During the 100-d period of feeding, feed intake per kg body weight did not differ (P < 0.05) between IUGR and NBW pigs or between control and glycine groups. Growth rates of NBW pigs supplemented with 1% glycine did not differ (P < 0.05) from those for NBW pigs without glycine supplementation. In contrast, growth rates of IUGR pigs supplemented with 1% glycine were 28%, 15%, and 10% greater (P < 0.05) than those for IUGR pigs without glycine supplementation during d 21–35, d 35–64, and d 65–120 of age, respectively. Growth rates of NBW pigs were greater (P < 0.05) than those for IUGR pigs without glycine supplementation during any experimental period. By d 120 of age, the body weight of IUGR pigs with glycine supplementation did not differ (P < 0.05) from that of NBW pigs. Collectively, our results indicate that dietary supplementation with 1% glycine (a low-cost supplement) beneficially improves their growth rate and economic returns. Supported by a USDA/NIFA grant.