Purpose: To review and analyze the published data on high-dose-rate brachytherapy as monotherapy in the treatment of prostate cancer. Methods: A literature search and a systematic review of the high-dose-rate (HDR) brachytherapy (monotherapy) prostate literature were performed on PubMed using "high-dose-rate, brachytherapy, prostate, monotherapy" as search terms. More than 80 articles and abstracts published between 1990 and 2013 were identified. Data tables were generated and summary descriptions created. Commentary and opinion was formulated through discussion and consensus based on the critical review of the literature and the author's combined personal experience and knowledge. Results: Thirteen articles reported clinical outcome and toxicity with followup ranging from 1.5 to 8.0years. Results were available for all risk groups. A variety of dose and fractionation schedules were described. Prostate-specific antigen progression-free survival ranged from 79% to 100% and local control from 97% to 100%. The toxicity rates were low. Genitourinary toxicity, mainly frequency/urgency, was 0-16% (Grade 3). Gastrointestinal toxicity was 0-2% (Grade 3). Erectile function preservation was 67-89%. The radiobiological, clinical, and technical features of HDR brachytherapy were reviewed and discussed. Conclusions: Consistently high local tumor control and low complications rates are reported with HDR monotherapy. It provides reproducible high-quality dosimetry, it has an advantage from a radiobiology perspective, and it has a good radiation safety profile. HDR brachytherapy is a safe and effective local treatment modality for prostate cancer.