Recently, another laser technology has been introduced for the surgical treatment of BPH, the potassium titanyl-phosphate (KTP) laser. This modality can also be used to vaporize obstructive prostate tissue, and has been studied through single arm clinical studies. Short-term results are promising, with significant improvements in voiding symptoms and urine flow rates as well as minimal associated morbidity. However, to date a randomized comparison study between HoLAP and KTP laser vaporization of the prostate has not been reported. A group of investigators with extensive experience with both procedures intends to objectively compare these two procedures in a randomized clinical trial.