A high prevalence of low bone mineralization is documented in adult patients with cystic fibrosis (CF). Osteopenia is present in as much as 85% of adult patients and osteoporosis in 13 to 57% of them. In children, studies are discordant probably because of different control database. Denutrition, inflammation, vitamin D and vitamin K deficiency, altered sex hormone production, glucocorticoid therapy, and physical inactivity are well known risk factors for poor bone health. Puberty is a critical period and requires a careful follow-up for an optimal bone peak mass. This review is a consensus statement established by the national working group of the French Federation of CF Centers to develop practice guidelines for optimizing bone health in patients with CF. Recommendations for screening and for calcium, vitamin D and K supplementation are given. Further work is needed to define indications for treatment with biphosphonates and anabolic agents.