Background: The main problem with using nebulized liposomal amphotericin (n-LAB) as prophylaxis for Aspergillus infection after lung transplantation is the lack of knowledge of its pharmacokinetics and its possible adverse effects. The aim of this study was to measure post-inhalation amphotericin B concentration in the respiratory tract and serum of lung transplant patients and assess the effects of n-LAB on respiratory function. Methods: Thirty-two consecutive bronchoscopies were performed on 27 lung transplant patients at two hospitals. Amphotericin B concentration in the first and third aliquot of bronchoalveolar lavage material was measured in steady state. The first aliquot approximates most closely the true amphotericin B concentrations in the proximal airway, whereas the third aliquot provides an optimum sample from the distal airway. Results: At 2 days, mean amphotericin B concentrations were 11.1 μg/ml (95% confidence interval [CI]: 16.5 to 5.7 μg/ml) and 9.0 μg/ml (95% CI: 14.3 to 3.8 μg/ml) in the first and third aliquot, respectively. Thereafter, concentrations declined progressively. At 14 days, concentrations were 3.0 μg/ml (95% CI: 4.4 to 1.5 μg/ml) in the first aliquot and 4.1 μg/ml (95% CI: 6.1 to 2.1 μg/ml) in the third aliquot (p = not statistically significant). Traces of amphotericin B (0.1 μg/ml) were found in serum samples from only 1 of 27 patients. Mean value of forced expiratory volume in the first second (FEV1) was similar before and after n-LAB. Conclusions: Amphotericin B concentrations after n-LAB remained high for 14 days, at adequate concentrations for prophylaxis of Aspergillus infection. No significant systemic absorption of amphotericin B was detected and no effect was observed on respiratory function. This promising prophylactic regimen warrants assessment in future clinical studies. © 2009 International Society for Heart and Lung Transplantation.