Cystic fibrosis (CF) is an autosomal recessive genetic disorder that disrupts ion transport across epithelial surfaces, impairing mucociliary clearance and predisposing patients to chronic, often refractory bacterial infections. At the Eliava Phage Therapy Center (EPTC) in Tbilisi, Georgia, we utilize bacteriophage preparations to treat chronic pulmonary infections caused by various bacterial pathogens, including Staphylococcus aureus, Pseudomonas aeruginosa, Achromobacter xylosoxidans, and Burkholderia cepacia. This case report describes the successful treatment of a CF-related infection in a male patient with a ΔF508 mutation using Pyophage and Intestiphage preparations, as well as customized phages developed against specific P. aeruginosa isolates. The efficacy of phage therapy was assessed by evaluating clinical improvement, pulmonary function, inflammatory markers, and bacterial burden. We observed improvement across all assessed parameters, including a complete eradication of P. aeruginosa in sputum culture tests. This case highlights the potential of phage therapy as a primary antimicrobial approach for the long-term management of pulmonary infections in patients with CF.