This article reviews the indications, techniques, and results of brachytherapy in the treatment of non-small cell lung cancer (NSCLC) and selected chest neoplasms. Various isotopes and techniques are used to place radioactive sources directly into a tumor, tumor bed, or the chest. Brachytherapy techniques can be tailored to the clinical situation and can be in the form of permanent interstitial volume or planar implants (radioactive sources permanently imbedded into the tumor or tumor bed) or in the form of temporary interstitial or endoluminal implants (where radioactive sources irradiate a tumor bed over a certain length of time and then are removed). These treatments can be delivered over a short interval (high-dose rate [HDR]) or over a more protracted time (low-dose rate). HDR treatments can be used intraoperatively to deliver a large dose of radiation to a determined target area with selective sparing of surrounding normal structures. Different methods of delivering HDR intraoperative radiation are under investigation. Most reports on brachytherapy for chest malignancies are retrospective and come from a few single institutions. Most of the published data relate to the treatment of NSCLC, but other intrathoracic malignancies, such as malignant pleural mesothelioma and malignant thymoma, have been treated with brachytherapy. To our knowledge, no major randomized trials accurately assess or confirm these retrospective studies yet, complicating the interpretation of these results. Nevertheless, brachytherapy is of value in selected situations and offers the clinician and the patient an innovative method of delivering conformal high-dose radiation to a defined target with preferential sparing of normal surrounding structures. With continued innovations in the development of radioactive isotopes, computerized treatment planning and targeting, and source delivery, brachytherapy should continue to offer an attractive alternative and complement to conventional treatment approaches, and may offer patients improved local control and survival.