Rationale: Bronchiectasis is a persistent and frequently progressive condition characterized by dilated and thick-walled bronchi retaining sputum. The main symptoms of bronchiectasis are cough and chronic sputum production. There is a state of constant colonization with bacteria, which frequently causes exacerbations. The presence of Pseudomonas aeruginosa is an unfavorable prognostic indicator and is associated with increased sputum production, more extensive bronchiectasis on HR-CT of the thorax, more hospitalizations and reduced quality of life. Until now, most patients with non-CF bronchiectasis who are colonized with P. aeruginosa receive inhaled tobramycin every other month, by use of a nebulizer. However, this delivery system has several disadvantages, like a low lung deposition and pollution with tobramycin in the surrounding environment. With an efficient dry powder inhaler (DPI), a three to six fold higher lung deposition compared to a nebulizer can be obtained. Therapy with a DPI is also less time consuming compared to nebulisation. Nebulised tobramycin is used most in routine care; there is also one, rather poorly characterized DPI for tobramycin available, though this DPI is not registrered for non-CF bronchiectasis. We will investigate dry powder tobramycin (DP tobramycin) in a novel device in patients with non-CF bronchiectasis colonized with P. aeruginosa.