Brachytherapy is a radiotherapeutic technique that allows the physician to implant radioactive isotopes into a body cavity or directly into tissue. Different radioisotopes have unique characteristics that the brachytherapist may utilize for a particular situation. The use of brachytherapy is part of standard radiation oncology practice in gynecological and head and neck cancer management. The prostate is approachable for interstitial implantation due to its close proximity to the perineum. Over 20 years ago, primitive methods of brachytherapy were utilized in the treatment of prostate cancer. However, poor results due to inconsistency in achieving adequate coverage of the entire prostate and poor patient selection caused this treatment modality to fall out of favor. Technological advances over the last decade have restored attention to brachytherapy for prostate cancer. Particularly important has been the development of transrectal ultrasound, new radioisotopes such as palladium-103, computer tomography, computerized dosimetry systems, and earlier diagnosis. Modern interstitial implantation utilizing transperineal template and transrectal ultrasound guidance has resulted in improved consistency in radiation dose delivery to the entire prostate. Early results are encouraging in terms of the relatively low morbidity of the procedure, improved local control rates, and biochemical progression free survival. This has resulted in an outpatient treatment that has high patient acceptance.