Allograft infection after lung transplantation has a significant impact on the outcome and can be a diagnostic challenge. The increased susceptibility of the pulmonary allograft to infection is due to its direct contact with environmental microbes by inhalation, concurrent immunosuppression, and the impaired clearance mechanisms after denervation of the transplanted lung. The possible spectrum of microorganisms infecting the allograft after lung transplantation is broad, but commonly includes Pseudomonas aeruginosa, cytomegalovirus, community-acquired respiratory viruses, and Aspergillus species. Prophylactic antimicrobial treatment regimens after surgery reduced the incidence of infections. However, preventive strategies for reducing infectious complications used by different transplant centers are still heterogeneous, and many questions regarding efficacy remain unanswered.