Cystic fibrosis is the most common potentially lethal autosomal recessive, genetic disease associated with pulmonary and pancreatic insufficiency. It is caused by variations in the CFTR (cystic fibrosis transmembrane regulator) gene. The most common mutation in the CFTR gene designated ΔF508, is found in only 33 per cent of CF patients in Pakistan. The variability in presentation and clinical severity of disease may be a function of genotypic-phenotypic factors. Our aim was to attempt to define the disease in this region and to lay the ground work for future mutational analysis. This study was a retrospective chart review was conducted to identify cystic fibrosis patients seen at the Aga Khan University Hospital over a 10-year period. Our study identified 56 patients diagnosed by a pilocarpine iontopharesis sweat test. A chart review was then done to look at the various clinical profiles. 58.3 per cent of our patients presented in the first 6 months of life supporting the hypothesis that CF may be a severe disease in Asians with an earlier age of presentation. Most of the patients (80.6 per cent) presented with pulmonary problems while 83.9 per cent had failure to thrive. The most frequently isolated pathogen was Pseudomonas aurgenosa in 87.5 per cent of the patients tested. 70 per cent of the patients died in the first year of life. The clinical parameters studied suggest a severe form of CF in Pakistani patients and provides a foundation for future studies to define genotype/phenotype correlations of the specific mutations involved in Pakistani CF patients.