Cystic Fibrosis (CF) is an autosomal multisystem recessive genetic disease. Patients with Cystic Fibrosis, oral bacteria related to dental and periodontal diseases that can also inhabit the lungs, increases the risk for systemic complications. Our study aimed at assessing oral hygiene status of cystic fibrosis adult patients. The study was conducted on 40 patients diagnosed with CF and 40 healthy participants. The following indices were included: Simplified Oral Hygiene (OHI-S), Approximal Plaque Index (API), Community Periodontal Index of Treatment Needs (CPITN), and a questionnaire. Obtained results proved that the API was 44.63% in the study group, indicating sufficient hygiene, and 37% in the control group, indicating quite good hygiene. Significantly higher OHI-S was found in the study group. It was found based on the analysis of treatment needs that home care and professional instructions on proper oral hygiene were more often needed in the control group compared to CF patients. In conclusion, the obtained API and OHI-S values in adult CF patients were indicative of satisfactory oral hygiene. Periodontal treatment needs assessed based on the CPITN index in patients with CF indicated the need for professional preventive treatments. An interdisciplinary dental care to support oral health could be recommendable in individuals with chronic respiratory diseases such as Cystic Fibrosis. Keywords: cystic fibrosis; systemic inflammatory disease; oral hygiene; periodontal treatment need