Abstract Aim To determine the growth and prevalence of extrauterine growth restriction (EUGR) in extremely low birth weight (ELBW) infants receiving enteral-only nutrition in a resource-restricted (RR) environment. Methods Information on nutritional intake, provided largely from fortified breastmilk, was collected retrospectively for 72 ELBW (<1000 g) infants admitted to Tygerberg Hospital, Cape Town, South Africa over a 1 year period. Anthropometric data for the first 49 postnatal days were compared to gender-specific INTERGROWTH-21st standards. Results Full enteral feeds (150 ml/kg) were reached by Day 10–14 with energy >100 Kcal/kg/day from Day 10, and protein >3.5 mg/kg/day from Day 14, onwards. Growth velocity remained below 15 g/kg/day at Day 49. INTERGROWTH-21st Z-scores decreased from −0.8 ± 1.1 at birth to −2.4 ± 1.5 at Day 49. Adequate weight growth velocity (≥15 g/kg/day) was associated with maternal hypertension, completed antenatal steroids, caesarean section delivery and small for gestational age status. Conclusion This is the first study to evaluate growth of ELBW infants in a RR setting where enteral-only nutrition, principally from fortified breastmilk, was the primary feeding option. The incidence of EUGR, although high, was similar to the incidence in well-resourced settings, where total parenteral nutrition is routinely provided. Lay summary Extra-uterine growth restriction (EUGR) is high in extremely low birth weight infants receiving enteral-only nutrition. However, EUGR rates are similar to infants receiving parenteral nutrition. Despite developmental immaturity, it is possible for these infants to achieve fetal growth rates. More aggressive feeding and fortification strategies may be necessary and will need to be balanced against the risk and fear of necrotizing enterocolitis. Enteral-only feeding regimens, especially in resource-restricted environments, should be audited regularly to ensure provision of feeds with the most optimal protein, and protein to energy ratios possible.