摘要:Background: Cystic fibrosis is a multisystemic disorder. It is the most common autosomal recessive disorder in whites that causes complications such as changes in bone density. Therefore, evaluating bone densitometry and serum levels of vitamin D in children with cystic fibrosis is the aim of our study.Methods: This study was performed on 54 children with cystic fibrosis. After recording demographic information, bone densitometry and serum levels of vitamin D were recorded. Chi-square and Pearson correlation tests were used to compare data.Results: Based on our study 53.7% of patients with CF had vitamin D less than 20 nmol / l. It was also found that based on lumbar BMD, 20.3% had a BMD less than 2.5 - Based on femoral BMD, 18.5% had a BMD less than -2.5. And our results demonstrated that there is no relation between BMD with vitamin D, calcium and phosphorus but it is significantly correlated with age, height, weight, and BMI.Conclusion: Decreased BMD is high in patients with CF; on the other hand there is a deficiency of vitamin D in more than 50% of these patients to whom vitamin D supplements should be prescribed along with the standard treatments. Further studies are also required to investigate the effect of other factors on BMD.