We describe 45 patients with cystic fibrosis (CF), diagnosed between June 1987 and May 1999, seen at the Hamad Medical Corporation, Qatar in the Arabian Gulf. Twenty-six of 32 families in the study were related and belonged to the same Bedouin tribe. The parents of 98% of these cases were consanguineous. Metabolic alkalosis and/or hypo-electrolytaemia were found in a large proportion of infants with CF. Cystic fibrosis in Qatari children is phenotypically variable with mild to moderate respiratory symptoms, and none of them died during this study. Among the non-Arabic-Asian patients, pulmonary symptoms were more severe, Pseudomonas colonization was earlier, pancreatic insufficiency occurred in infancy and four died in early life.