Breast cancer, a common malignancy in women, is a major cause of cancer-related deaths. Metastases to the thorax are common in patients with breast cancer. Metastases can manifest radiographically as pulmonary nodules, lymphangitis carcinomatosa, endobronchial masses, intrathoracic adenopathy, pericardial or myocardial masses and pleural effusions. Additionally, pulmonary abnormalities occur after radiotherapy, chemotherapy and autologous bone marrow transplantation. Knowledge of the various intrathoracic manifestations of metastases and complications of therapy is important in staging and evaluating patients with breast cancer and deciding on the most appropriate treatment.