Abstract. Pseudomonas aeruginosa and Staphylococcus aureus are bacterial pathogens frequently associated with pulmonary complications and disease progression in cystic fibrosis (CF) patients. However, these bacteria increasingly show multiple resistance to antibiotics, necessitating novel management strategies. One possibility is phage therapy, where lytic bacteriophages (phages; bacteria-specific viruses) are administered to kill target bacterial pathogens. Recent publication of case reports of phage-therapy treatment of antibiotic-resistant lung infections in CF has garnered significant attention. These cases exemplify the renewed interest in phage therapy, as an older concept that is newly updated to include rigorous collection and analysis of patient data to assess clinical benefit, while informing the development of clinical trials. As outcomes of these trials become public, the results will valuably gauge the potential usefulness of phage therapy to address the rise in antibiotic-resistant bacterial infections. In addition, we highlight the further need for basic research on accurately predicting the different responses of target bacterial pathogens when phages are administered alone, sequentially or as mixtures (cocktails), and whether within-cocktail interactions among phages hold consequences for the efficacy of phage therapy in patient treatment.