Background: Vitamin D deficiency is common in young cystic fibrosis (CF), and is due to the impaired absorption of fat-soluble vitamins, decreased sun exposure, and suboptimal intake of vitamins-containing foods and/or supplements. Given that childhood is a critical period for the accrual of bone mass, with 90% peak bone mass laid in the first two decades of life, it is essential that optimal vitamin D levels are achieved in this time frame. Methods: We conducted a retrospective review from January 1, 2012 to January 1, 2013, through which we reviewed levels of vitamin D and correlated with bone profile, liver function tests, lung function, genotype, age, dual-energy X-ray absorptiometry scan and body mass index z score. Results: Of the 95 children with CF, 6 were excluded due to incomplete data, bringing our study population to a total of 89 children. Results showed 77.5% vitamin D deficiency (mean 59.42 nmol/L). No significant statistical correlation was found between vitamin D and the parameters described. Protocol supplementation did not raise vitamin D to therapeutic level in 63.2% of the study population. Those with genotype delta 508 (homozygous/heterozygous) had 92% vitamin D deficiency. Conclusions: We attribute the non-responder group to vitamin D to poor compliance. Compliance level could not be addressed because our study is a retrospective review. Thus, further research is needed to define implications of pulmonary exacerbations on vitamin D and vice versa. Doing so can help assess the implication of genotype influence on vitamin D.