Preterm infants whose mothers are unable to produce sufficient breast milk are increasingly being supplemented with pasteurised donor human milk (PDHM) instead of commercial preterm infant formula. Concerns have been raised that this practice can result in reduced growth. This retrospective clinical audit collected data from the medical records of a cohort of preterm infants (≤30 weeks gestational age) receiving either ≥28 d of PDHM (n 53) or ≥28 d of their mother’s own milk (MOM, n 43) with standard fortification supplied to both groups during admission. Weight growth velocity was assessed from regained birth weight to 34+1 weeks’ postmenstrual age (PMA); and weight, length and head circumference were compared at discharge and 12 months (corrected age). At 34+1 weeks’ PMA, the weight growth velocity (g/kg per d) was significantly lower in the PDHM group (15·4 g/kg per d, 95 % CI 14·6, 16·1) compared with the MOM group (16·9 g/kg per d, 95 % CI 16·1, 17·7, P=0·007). However, the increase was still within clinically acceptable limits (>15 g/kg per d) and no significant difference was observed in the weight between the two groups. There was no significant difference in weight between the groups at discharge or at the 12-month corrected gestational age review. Although we demonstrated a significant reduction in the weight growth velocity of preterm infants receiving PDHM at 34 weeks’ PMA, this difference is not present at discharge, suggesting that the growth deficit is reduced by supplementation before discharge.