Introduction: Long-term survivors of cystic fibrosis (CF) have a dramatic increase in the risk of osteoporosis and incident fracture. The objective of this work is to characterize a CF related bone disease in a Portuguese cohort of CF patients. Methods: We performed a cross-sectional, observational study on a cohort of CF adult patients. Clinical status, laboratory parametres, nutrition, lung function tests, genetics and bone mineral density (BMD) data were collected from a CF reference centre. Results: Of 30 patients, 53.3% were males (n=16). Median age was 32.5 (27.0; 32,5) and median body mass index (BMI) was 22,04 (19,85; 24,55), with 4 patients (13.3%) being underweight (BMI<18.5 kg/m²). Four patients (13.3 %) were diagnosed with osteoporosis and 15 patients (50%) has low BMD. Among them, 2 (6.7%) had fragility fractures. A moderate correlation was found between the lumbar spine (LS) BMD and BMI and, as expected, femural neck BMD and LS BMD has moderate to strong correlations with BMD Z scores. Conclusion: Despite the young middle age we found a high prevalence of low BMD and osteoporosis in patients with CF. Early recognition and treatment are the most effective strategies for reducing the morbidity due to osteoporosis in these patients.