The objective of interstitial laser coagulation (ILC) of benign prostatic enlargement is to achieve a marked volume reduction and to decrease bladder outlet obstruction and lower urinary tract symptoms with minimal morbidity. Coagulation necrosis is generated well inside the adenoma by means of specifically designed laser applicators combined with either a Nd:YAG laser or a diode laser. Because the laser applicators can be inserted as deeply and as often as necessary, it is possible to coagulate any amount of tissue at any desired location while preserving adjacent structures such as the urethra. Postprocedural, the intraprostatic lesions result in secondary atrophy and regression of the prostate lobes, rather than sloughing of necrotic tissue. Several single-armed and randomized studies indicated the effectiveness of interstitial laser coagulation of BPH-syndrome. Marked improvements in AUA score, peak flow rate, residual urine volume and prostate volume were reported. Pressure-flow studies demonstrated a sufficient decrease of the intravesical/detrusor pressure, urethral opening pressure and urethral resistance. Long-term results demonstrating sustained success for up to 3 years were reported on a series of 394 patients. ILC is suitable to debulk even large prostates and to treat highly obstructive patients. Therefore, ILC can be seen as a true alternative to TURF with certain advantages, such as almost no serious morbidity and with certain disadvantages, such as the need for postoperative catheterization. However, ILC can be done under local anesthesia and does not require hospitalization.