In Germany, many adult patients with cystic fibrosis are still treated by pediatricians. There are still not enough specialists for internal medicine (and particularly pulmonologists) with sufficient knowledge about cystic fibrosis for the treatment of estimated 2000 adult CF-patients. The knowledge about the three basic principles of cystic fibrosis therapy--regular high-dose antibiotics, high-energy and high-fat nutritional support and specific physiotherapy--has to be transferred to adult medicine in order to assure competent care for this "new" group of patients. Cystic fibrosis is also becoming more and more and more important in the field of intensive care medicine and transplantation. Specific diagnostic procedures are important in adult respiratory medicine in order to confirm or exclude late manifestations of the disease. Understanding of the genetic basis of cystic fibrosis and the correlations between genotype and phenotype is beginning to emerge.