In patients with cystic fibrosis (CF), respiratory infections with the opportunistic bacterial pathogen Pseudomonas aeruginosa have a major impact on morbidity and mortality. Aminoglycosides, especially tobramycin, have been used successfully to combat these infections. Aminoglycoside penetration of bronchial secretions is poor when the antibiotic is administered intravenously. Nebulization allows direct delivery of the drug to the sites of infection within the airways, while avoiding systemic exposure. Published clinical data show that inhaled tobramycin reduces the bacterial load, improves lung function and reduces the number of hospital admissions. Inhaled tobramycin has been used successfully to eradicate P. aeruginosa in patients with early infection. Maintaining clinical benefits requires chronic tobramycin treatment, and the concept of chronic intermittent inhaled treatment (typically, alternating drug and drug-free periods of 28 days) was introduced to minimize the emergence of aminoglycoside resistant P. aeruginosa strains. Other therapeutic advances include the development of different tobramycin formulations and nebulizers that reduce delivery time without compromising efficacy. An optimal treatment regimen for patients with CF with early or intermittent P. aeruginosa infections remains a high priority to maintain long-term lung health.