Background. Cystic fibrosis (CF) patients are in increased risk of osteoporosis. We aimed to determine the osteoporosis prevalence in an adult CF cohort and investigate calcium metabolic parameters and clinical status' association with bone mineral density evaluated by dual X-ray absorptiometry scan. Methods. We performed a cross section database study of adults at a tertiary CF Center. Z scores were applied for patients < 50 years of age and T scores for patients > 50 years of age. Results. One hundred twenty-five patients were included. Compared to nonosteoporotic patients, osteoporotic patients (15%) had significantly lower percent predicted forced expiratory volume in 1 second (pp ^FEV1 ), lower body mass index, higher frequency of CF-related diabetes and chronic lung infection, and higher high-sensitive C-reactive protein and glycated hemoglobin levels. Vitamin D was not associated with any outcome. In multivariate analyses, only pp ^FEV1 and female gender were independently associated with Z scores. Conclusions. Osteoporosis in CF occurs with deteriorating clinical status while the role of calcium metabolism seems minor. Gender specific and dysglycemic impact on bone status should be investigated further.