Cystic fibrosis (CF) is an incurable, autosomal recessive hereditary genetic disease. Since the end of 2009, CF has been diagnosed through a screening of newborn babies. This method is capable of identifying the majority of CF in infancy before the disease actually develops and manifests itself, thus allowing for an immediate treatment. In recent years, a targeted and personalized therapy has also been used as an additional treatment. This thesis focuses on comparing the quality of life of patients who were diagnosed with CF through screening performed at an early age with those who were diagnosed at a later age, as well as on the impact of modern therapy on the improve-ment of the monitored parameters. Clinical data were provided by the Institute of Medical Genetics and Genomics at the University Hospital Brno (MUDr. Renata Gaillyová, Ph.D.) and by the Department of Paediatric Infectious Diseases at the Uni-versity Hospital Brno (Head Physician MUDr. Miriam Malá, Ph.D.; Head of the De-partment MUDr. Lukáš Homola, Ph.D.)