We have reviewed the outcome and feeding of the 28 cystic fibrosis (CF) infants diagnosed at St James's University Hospital, Leeds, during 15 years between 1974–1988. During this period most infants were fed on either standard formula milk feeds or a lower fat, higher protein mix (CF milk). It was the practice to prescribe pancreatic enzymes from the diagnosis of CF, wean the infant on to solids between 2 and 3 months of age and provide extra calorie supplements if infants were not thriving adequately. The mean weight at birth (s.d.) was 3.33 (0.45) kg and at 12 months was 9.56 (1.21) kg. It is concluded that CF infants provided with adequate energy intake and appropriate pancreatic enzymes should thrive satisfactoril