Cystic fibrosis (CF) is the most common autosomal, recessive-inheritance genetic disorder caused by a mutation in the cystic fibrosis transmembrane conductance regulator (CFTR). The disease phenotype has a broad spectrum, with more than 2,000 different potentially pathogenic mutations in the CFTR gene. Mutations are classified into five groups, of which grades 1 and 3 show more severe diseases than grades 4 and 5. The genotype-phenotype correlation is weak in relation to pulmonary involvement, whereas pancreatic insufficiency is more strongly correlated. Exocrine pancreatic insufficiency is the most common gastrointestinal complication of CF, resulting in reduced production of pancreatic enzymes, resulting in fat and protein malabsorption. Undiagnosed and under-treated pancreatic disease leads to steatorrhea, malnutrition and a deficiency of fat-soluble vitamins. 15 to 20% of pancreas-insufficient CF patients develop pancreatitis. Decreased endocrine function of the pancreas leads to the development of CF-associated diabetes, which has now become the most common comorbidity. Early detection and substitution treatment of pancreatic exocrine and / or endocrine dysfunction in CF is key to a better and healthier life expectancy for patients. The aim of the clinical study "Exocrine and endocrine pancreatic examination in cystic fibrosis" is to collect data prospectively in a multi-centric manner in order to analyze the epidemiology, course, efficacy of drug therapy, occurrence of drug-induced adverse events in CF, and factors that influence exocrine and endocrine function progression. Prospective data collection with annual follow-up visits for 7 years is planned for the planned study, involving patients diagnosed with CF. Recognizing early markers of pancreatic exocrine and endocrine dysfunction and investigating underlying mechanisms may open up new therapeutic approaches and strategies for improving the quality of life and quality of life for the majority of CF patients.