Purpose of review Clinically mandated transbronchial biopsy is universally regarded as the most efficient tool to establish pathology in the allograft. However, the utility of surveillance transbronchial biopsy to facilitate early detection and treatment of acute pulmonary allograft rejection is a matter of current debate. The purpose of this review is to summarize the evidence for and against the performance of surveillance bronchoscopy postlung transplantation, to discuss the risk/benefit ratio and the application of this procedure in the individual patient. Rent Findings Detection of silent acute rejection of the pulmonary allograft remains an important benefit of surveillance bronchoscopy although definitive evidence for a positive impact on survival or prevention of development of the bronchiolitis syndrome (BOS) is yet to be demonstrated. Perhaps the wrong target has been the focus as new evidence suggests that high grade lymphocytic bronchiolitis is the important independent risk factor for the development of BOS and death after lung transplantation. Providing effective therapies for lymphocytic bronchiolitis can be developed there is now strong support for performance of surveillance transbronchial biopsy. Most studies attest to a low risk of severe complications. Summary Surveillance bronchoscopy is useful to detect asymptomatic acute rejection but also to determine the presence and severity of lymphocytic bronchiolitis, which should be the new target of therapeutic endeavours. It is acknowledged that the true risk/benefit ratio of surveillance bronchoscopy may differ between programs so each case deserves individual consideration.