Regarding the new discoveries in medicine and their implementation in daily practice, people whose illnesses were once confined to childhood, grow up and are treated by internal medicine specialists. Transition to adult care shouldn't be a one-time event. It should be a planned and comprehensive process in which the adolescent gradually learns about his illness, gains skills in therapy, learns how to be proactive in maintaining a healthy lifestyle and fully takes over the responsibility that was in the hands of the parents. Cystic fibrosis is one of the illnesses where the transition from pediatric to adult health care is essential. It is an autosomal recessive hereditary multisystemic illness of progressive course that begins in utero and progresses after birth. Median predicted age of survival of patients born today is about 50 years. The number of complications and involvement of various organ systems increases with the age of the patient. The disease is rare, characterized by a highly variable clinical course and expression of the disease. Therefore, optimal treatment for these patients is provided in specialized centers that bring together a multidisciplinary team of health care providers with a special interest in this disease, which guarantees comprehensive care. Such a center exists in Croatia, since 2017: the Cystic Fibrosis Center for Children and Adults that operates within the University Hospital Centre Zagreb. According to data from 2017, it takes care of 93 patients, 41 (45%) of which are adults. Transition to adult care is organized according to a patient-focused model as a planned and continuous process. Members of the multidisciplinary team get acquainted with the specifics of each patient during childhood and adolescence and at the appropriate time meet the patient. The optimal time for the act of transfer to adult care is determined by the consensus of experts from the Center, considering the characteristics of the patient and stage of disease. This ensures a smooth transfer and continuous treatment following the same standards, which is the goal of a comprehensive and well-designed, structured transition to adult care.