Introduction: Recent developments in treatment have steadily raised the median predicted age of survival for people with Cystic Fibrosis (CF). We report the health-related quality of life (HRQoL) in CF adult patients and correlate our findings with the patients’ demographic characteristics. Material and methods: The Cystic Fibrosis Quality of Life (CFQoL) questionnaire was answered by 77 CF adult patients. The questionnaire included questions pertaining to age, sex and level of education and covered eight sections of functioning. Results: The highest score was reported in the “Social Functioning” section, while the lowest in the “Concerns for the Future” section. When different age groups were compared, statistical significances were reported in “Physical Functioning”, “Interpersonal Relationships”, and the “Career Concerns” section, with older patients reporting statistically higher HRQoL scores than younger ones (p < 0.005). No statistically significant difference was reported amongst the scoring between male and female CF patients. When different educational levels were compared, patients that had received a higher educational training scored statistically higher in all but one sections of the questionnaire when compared with patients of a lower educational level (p < 0.005). Conclusion: More than half Greek adult CF patients report that they are capable to participate in social activities but most of them are worried about the outcome of their disease and its effect on their lives.