Decreased bone mineral density (BMD) is an emerging problem for clinicians who care for children with Cystic fibrosis (CF). The aim of this study was to determine prevalence and assess risk factors for reduced BMD in our adolescent population with CF. All bone densitometry scans (n=99) performed on children (n=79) with a mean age 13.6 (10-19.2) years over a 7 year period (2000-2007) were reviewed. Patient records were reviewed for correlating clinical data. Low BMD is frequently present in adults and children with variable reports (36-66%). In our study, BMD expressed as z score of L2-L4 spine was reduced in a total of 50% children with a preponderance of males. Bone demineralization was strongly associated with increasing age (p=0.03), diminished lung function (p=0.027), reduced body mass index (p=0.001) and treatment with oral corticosteroids (p=0.02).