Prostate cancer has been treated with low-dose rate (LDR) brachytherapy for early localised disease in the form of permanent seed implants, with all its inherent problems in terms of dosimetry and seed migration. High-dose rate (HDR) brachytherapy has mainly been utilised as a boost to external beam radiotherapy (EBRT) in patients with locally advanced disease. However, limited studies investigating HDR as a monotherapy for early local disease are yielding promising results in terms of biochemical control and reduced toxicity. With the ability to optimise the plan and conform the dose, dose escalation can be achieved whilst sparing normal tissue. Recent studies to assess the α/β ratio of prostate cancer have shown this to be low, making this tumour sensitive to large fractions or hypofractionation. The HDR delivery and large fraction sizes may be advantageous in tumours sensitive to radiation fraction size making HDR brachytherapy the treatment of choice over LDR brachytherapy and EBRT.