Cystic fibrosis is an autosomal recessive inherited disease, one of the most common inherited diseases of the white population. Since no epidemiological survey on the exact prevalence in the Republic of Croatia has been conducted so far, it is estimated that the number of patients is around 200. The disease is multisystemic, and each member of the interdisciplinary team is expected to make maximum efforts to ensure that complex patient care is complete. The aim of this paper is to determine the extent to which adherence affects the patient's functional status and quality of life, and how important nursing education for adult patients with cystic fibrosis is in improving it. The study was conducted on 26 patients at the Clinic for Pulmonary Diseases Jordanovac, Clinical Hospital Center Zagreb, using anonymous licensed questionnaires and anamnestic data while conducting structured nursing education to raise awareness of the importance of daily and lifelong treatment. In addition to demonstrating a moderately positive correlation between BMI and FEV1, extent to which participants adhered to it has been identified with the main causes of non-adherence to prescribed therapy before and after education. Although the initial results of the research show that there are slight positive shifts in the adherence of the subjects before and after, statistics significance was not proven, which is related to the small sample and the short period of time since the education was conducted. This only goes to show that education must involve the entire team of healthcare professionals and to be constant and consistent. Adherence has a major impact on functional status and quality of life, the patient themselves and their responsible understanding of the disease play a key role in improving adherence.