OBJECTIVES: To assess efficacy and safety of dornase alfa in the treatment of cystic fibrosis (CF) in children and adults. METHODS: Systematic review of Medline, EmBase, CENTRAL and clinicaltrials.gov databases was conducted. The references from relevant articles and abstracts from conferences were also examined to identify any additional studies. Each full-text article was critically appraised with use of the Jadad Scale. Clinical practice and CF treatment procedures in Poland were consulted with clinical experts. Placebo and treatment without dornase were identified as potential comparators. Changes in FEV1, FVC, and FEF25%-75%, exacerbation of respiratory symptoms, body mass change, use of drugs, number of days spent at home due to CF, hospitalizations (number and length), ambulatory visits, quality of life, mortality rate, treatment acceptance by patient and safety were assessed and compared based on the review results. RESULTS: Among 294 reports found, 17 publications concerning 12 randomized clinical trials were included in the analysis. The meta-analysis of available data regarding changes in FEV1 after 1, 3, 6 months and 1 and 2 years showed better results with dornase therapy. The use of dornase also improved pulmonary function measured in FVC. Exacerbations of respiratory symptoms were less frequent (by 20% when dornase alpha was administered once daily and by 34% when administered twice daily), which resulted in fewer hospitalizations. Patients treated with dornase required less frequent courses of intravenous antibiotics and spent fewer days at home due to CF. Safety analysis showed a higher risk of rash, voice alteration and pharyngitis with dornase. Mortality was similar among groups. CONCLUSIONS: Dornase alfa is an effective (improves respiratory function, reduces CF symptoms, dyspnea and respiratory system exacerbations) and safe therapeutic option.