Prostate cancer shows a large prognostic spectrum that ranges from indolent to lethal forms that can be cured by two extreme kinds of therapy: “doing nothing” (“active surveillance/watchful waiting”) or “destroying prostate” (“surgical or radio-therapeutic treatment”). The distance between these two extremes has been covered by the concept of focal therapy, which aims at treating only the affected part of the prostate (the “index lesion”), using coagulative necrosis in prostatic cells, obtained by increasing local temperature. The aims of focal therapy are the same of the traditional one (surgery or radiotherapy), but with some advantages as: the mini-invasiveness, the reduced incidence of side effects (in terms of urinary incontinence and sexual impotence), the adaptability to the concept of focal therapy, and the short hospitalization. The modalities currently available are transrectal prostatic thermoablation with high-intensity focused ultrasound, focal laser ablation, irreversible electroporation, and photodynamic therapy.