Abstract Purpose Laser prostatectomy has evolved as a less invasive method of relieving bladder outlet obstruction due to prostatic enlargement. The elimination of adenomatous tissue by laser induced coagulation necrosis theoretically avoids the sequelae of fluid absorption noted during traditional transurethral resection of the prostate. However, to our knowledge no accurate determination of fluid absorption during laser prostatectomy has been performed to date. Materials and Methods A technique previously described to determine the amount of irrigant absorbed during transurethral resection of the prostate measures breath ethanol levels using a standard alcohol breath analyzer during the procedure after a predetermined amount of ethanol is added to the irrigant fluid. This method was used in 4 men undergoing laser prostatectomy. Results All 4 subjects had ethanol levels of 0 throughout the operation, indicating that little or no irrigant fluid was absorbed. Conclusions We demonstrated in a quantitative manner that fluid absorption during laser prostatectomy is almost nil and patients are, indeed, at no risk for the transurethral resection syndrome.