We describe the clinical features of six cystic fibrosis (CF) patients from Saguenay Lac-Saint-Jean who bear rare genotypes. Two patients with a delta F508/I148T genotype had pancreatic insufficiency, as did two patients compound heterozygous for the 621 + 1G-->T mutation who also had a major growth retardation. One CF adult who carried a delta F508/Q890X genotype had meconium ileus and bronchiectasis. The sixth patient (A455E/R117C) had borderline sweat chloride concentrations; the diagnosis of cystic fibrosis had remained doubtful until the molecular analysis showed the presence of two CF mutations. The seventh patient with a delta F508/R1158X genotype experienced several complications and is now 43 years old.