Cystic fibrosis related diabetes (CFRD) is associated with higher morbidity and 6 times higher mortality. In females, it occurs 5 years earlier compared to males. After 18 years of age, prevalence of CFRD increases and ranges between 12 and 34%, after 30 years it affects 35–50% of all patients. Prospective studies demonstrated deterioration of nutritional status and pulmonary functions 2–4 years prior diabetes onset; therefore, an early recognition of CFRD is a prerequisite for a successful management of CF patients. Insulin therapy of CFRD may delay progression of pulmonary changes. Pulmonary functions do not deteriorate within 5 years after onset of insulin therapy, in parallel with improved nutritional status. Screening of CFRD is based on oral glucose tolerance test (OGTT) after 10 years of age (golden standard). An additional intravenous glucose tolerance test (IVGTT) is provided in subjects with impaired glucose tolerance or diabetes mellitus to detect insulinopenia and to start individualised therapy. Regarding the prevalent finding of insulinopenia, an early insulin therapy is started as early as possible if necessary to negativprevent serious consequences of developing clinical diabetes on nutritional status and pulmonary functions. Special nutritional team takes care of diabetic diet in CFRD. In these subjects, diet is based on different principles in comparison to other diabetes subtypes. The food energy content has to be substantially increased and carbohydrates only moderately regulated. Any unexplained deterioration of nutritional status or pulmonary functions in CF patients should be suspected of CFRD.

        Key words: cystic fibrosis related diabetes, screening, therapy, insulin, OGTT, IVGTT