There has been a shift in recent years on the treatment of low- and intermediate-risk prostate cancer from the whole-gland prostatectomy or radiotherapy, in the attempt to avoid overtreatment of clinically insignificant disease and prevent unnecessary treatment-related side effects. Focal therapy for prostate cancer encompasses a few different modalities with the aim of targeting an ‘index lesion’ of cancer within the prostate, without having to perform radical whole-gland treatment, serving as a middle ground for patients who seek treatment, while minimising potential side effects by maintaining as much normal prostate tissue as possible. This chapter aims to summarise the published data on focal therapy, covering several modalities. It also addresses the published data and reviews on focal therapy for prostate cancer. PubMed, Google scholar, and Cochrane Library were searched, with emphasis on recent multicentre studies, examining the role for focal therapy, the index lesion, disease localisation, and a few focal ablation strategies. Cryotherapy, high-intensity focused ultrasound, laser ablation, irreversible electroporation and focal brachytherapy have all shown promising initial data as an alternative option to whole-gland therapy in intermediate-risk prostate cancer, with varying degrees of oncological effectiveness on failure-free survival/ re-treatment rates, and metastasis-free survival, as well as effects on urinary and sexual function. All modalities require further research into oncological effectiveness and safety. Focal therapy shows promise as a viable option for the treatment of carefully selected patients with well-defined intermediate-risk prostate cancer, although further research, clinical trials and long-term data is still required, and patients require close follow-up.