Various minimally invasive modalities that are aimed at alleviating lower urinary tract symptoms employ heat-induced ablation of hyperplastic prostatic tissue. Following extensive studies, most of these modalities were eventually abandoned. High-energy transurethral microwave thermotherapy has survived, however, and has gained a firm position as a therapeutic modality, along with transurethral resection of the prostate. Recent research addressed fundamental issues of mode of action of microwave treatment, and revealed the overall efficacy of this treatment, determined new indications, and rendered high-energy transurethral microwave thermotherapy more acceptable to the patients. Insights into intraprostatic vascularization and treatment monitoring were also gained as a result of these global research efforts.