Previous studies have documented a 75 to 80 percent mortality rate in infants (less than 12 months) with cystic fibrosis who present with RF/MV. We investigated the current outcome of these patients by comparing the outcome of five infants with cystic fibrosis and RF/MV between the years 1980 and 1986 with that of age-matched control subjects with cystic fibrosis and no respiratory failure. Recent Shwachman scores and the number of hospitalizations during the study period were used to assess outcome. All study cases were alive one to six years after the episode of RF/MV. Their mean Shwachman score (83 [range: 70 to 95]) did not differ from the recent mean Shwachman score (78 [range: 50 to 95]) of the control group. Number of hospitalizations did not differ between groups. We conclude that the outcome of infants with cystic fibrosis whose initial presentation is RF/MV is not as grave as once thought. If indicated, infants with cystic fibrosis and respiratory failure should be ventilated.