A recent surge in publications on low dose rate permanent seed brachytherapy prompted us to review the currently available literature in order to provide a summary of the therapy. To this end, we composed a comprehensive review on the available English language publications in PubMed, EMBASE, and Google Scholar. The general principles of seed brachytherapy are discussed, along with radiobiology and technical aspects. Seed brachytherapy has been increasingly used in various sites for primary treatment, and is considered to be particularly useful in cases of reirradiation and otherwise untreatable malignancies. In recent decades, there have been considerable advances in the technology used in seed brachytherapy, including steps to prevent the migration of seeds, reduce personnel exposure to radiation, and use of sophisticated 3-D planning for better dosimetric results, which have ultimately translated into better clinical outputs. Technical advances in seed brachytherapy have lagged behind those in external beam radiotherapy and high dose rate brachytherapy; however, there is renewed interest due to encouraging clinical results in the primary setting, as well as reirradiation for recurrent disease across several sites.