For the treatment of patients with cystic fibrosis, recombinant human deoxyribonuclease I is widely used. Deoxyribonuclease I has a positive effect on lung function and the number of hospitalizations. Deoxyribonuclease I is currently administered by nebulization, which is an inefficient administration method. For expensive drugs, such as deoxyribonuclease I, dry powder inhalation would be advantageous due to increased deposition efficiency, patient mobility and compliance. Furthermore, a significant cost reduction may be obtained. The current status of deoxyribonuclease I in the management of cystic fibrosis was investigated and special attention given to the developments in delivery systems, such as dry powder inhalation. It is estimated that if dry powder inhalation of deoxyribonuclease I could be used, a reduction in the cost-effectiveness ratio of approximately 40% can be obtained as compared with nebulization.