The indications, risks and benefits of surgical treatment of benign prostatic hyperplasia (BPH) have recently been scrutinized, and interest in the development of less invasive alternative nonsurgical approaches has emerged. Among the nonsurgical alternatives, thermal treatments have been clinically introduced for a few years but are still under evaluation. Microwaves and radiofrequency waves are generated by various devices applied by the transrectal or transurethral approach, with different treatment and temperature schedules. Results achieved with the various devices did not show large significant differences. Improvement is mainly observed by a decrease in irritative symptoms rather than by modifications of obstructive parameters. The placebo effect must not be underestimated in all these new alternative methods. Fifty percent of patients in retention and unfit for anesthesia voided satisfactorily after thermal treatment. Pathological studies of operative specimens after transurethral thermotherapy showed coagulative necrosis with destruction of smooth muscle and glandular components. The destruction of α-receptors or sensory nerves in the prostate stroma is a possible explanation for the reduction of irritative symptoms. No significant histological lesions were found however after transrectal hyperthermia. Various factors such as differences in tissue thermosensitivity, tissular architecture and thermoregulation related to variation in the prostate blood supply may all play a part in the final heating effect and determine the clinical response for a given patient. Better understanding of these various factors may improve patient selection. Although thermal treatment of BPH cannot be seen as a substitution for surgery, it may represent an alternative option in selected patients essentially to alleviate irritative symptoms. Many aspects of this new technological approach remain controversial, and further large-scale randomized sham studies and long-term follow- up are mandatory before the definitive place of thermal treatment of BPH can be established.