Cystic Fibrosis (CF) is a recessive autosomic genetic disease with an incidence in mediterranean countries of about 1:3500 born alive. In Italy the considerable genetic variability makes it difficult to identify all the homozygous subjects and, consequently, to estimate the incidence of the disease in healthy carriers. The disease is evolutive and affects various systems, most of all the respiratory and gastrointestinal systems. Not many years ago, when the clinical definition of CF was first introduced, average survival did not exceed the pediatric age. Nowadays with ever advancing diagnostic and therapeutical techniques many CF patients survive until an adult age. It is therefore necessary to plan adequate health service interventions so as to satisfy as much as possible the needs of both the patients and their families. To this end data collected since 1.1.1988 by the Italian registry for CF (year of birth, sex, region of birth and residence, diagnosis procedures, results of sweat test, pancreatic insufficiency, DNA analysis, status: alive, dead, lost to follow up) of all the patients, diagnosed in the 18 Reference Centres and the 3 local Centres for CF, have proved to be extremely useful. Since the birth of the Registry on 31.12.1997, data relating to 2458 patients alive on 1.1.1988 and 1159 born during the last ten years, for a total of 3617 subjects (1756 females and 1861 males), have been recorded. As already mentioned a considerable increase in life expectancy of CF patients (from 1988 to 1990 the average age of death was 14 years, from 1994 to 1997 it was 19) and a consequent increase in the percentage of adult patients have been observed.