Bone marrow transplantation (BMT) is a successful and recognised treatment option for patients with a number of haematological and non-haematological malignant and non-malignant conditions. Pulmonary complications both infectious and non-infectious are common after BMT. Multiple factors are thought to contribute to pulmonary complications, including the type and duration of immunological defects produced by the underlying disease and treatment, the development of graft-versus-host disease (GVHD), and the conditioning regimens employed. These complications are classified as early or late, depending on whether they occur before or after 100 days from transplantation. Early non-infectious pulmonary complications typically include pulmonary oedema, upper airway complications, diffuse alveolar haemorrhage, cytolytic thrombi, and pleural effusion. Bronchiolitis obliterans, veno-occlusive disease, and secondary malignancies occur late after BMT. Idiopathic pneumonia syndrome, GVHD, and radiation induced lung injury can occur in early or late period after BMT.