Two year follow-up of 80 surviving preterm babies from a controlled trial of surfactant replacement is reported. There were no statistically significant differences in rates of hospital admission, respiratory infections or antibiotic treatment. Wheezing, skin rashes and food intolerance were reported by parents with similar frequency in each group. Weight, length and occipito-frontal circumference were similar at all ages up to and including 2 years. Median developmental quotient (Griffiths scales) was 100 in the treated group and 95 in the control group (P = 0.053). Rates of cerebral palsy were similar in each group although milder forms predominated in the treated group. It is concluded that artificial surfactant (dipalmitoylphosphatidylcholine and high-density lipoprotein) replacement at birth is not associated with adverse long term effects on preterm babies.