Objective: To investigate the effects of rehabilitation methods on leg muscle function and functional performance in cystic fibrosis. Data sources: A literature search was conducted in PubMed (MEDLINE), Scopus and the Cochrane Library from inception to October 12, 2020. A secondary hand search through reference lists from identified articles was conducted. Review methods: Three authors independently checked the full-text copies for eligibility of relevant articles. Randomized controlled trials were included. Methodological quality was assessed using the Physiotherapy Evidence Database scale. The PRISMA guidelines were followed. Results suggestive of leg muscle function (e.g. strength, power, endurance, and fatigue) and functional performance were reported. Results: The search identified 8 studies (233 patients). The overall quality of these articles was good. Rehabilitation modalities investigated were physical exercises (aerobic, anaerobic and resistance training) ( n = 7) and neuromuscular electrical stimulation ( n = 1). Most studies ( n = 4) reported on the effects of combined aerobic and resistance training and showed improvement on leg strength when exercises were supervised. Aerobic training alone or the use of neuromuscular electrical stimulation also enhanced leg strength, whereas anaerobic training did not. Two studies evaluated leg fatigue and found no improvement compared to standard care. One study assessed the effect of exercises on functional performance and found no improvement when compared to standard care. No studies emphasized the impact of rehabilitation methods on leg muscle endurance or power. Conclusion: Combined aerobic and resistance training enhances leg muscle strength in cystic fibrosis. There is insufficient data on other leg muscle outcomes, nor on alternative rehabilitation strategies.