Abstract: A method and system for multiple microphone photoacoustic leak detection and localization. The leak detection technique uses photoacoustic sounds produced by the interaction of a carbon dioxide (CO2) laser turned to 10.6 microns and a photoactive tracer gas, sulfur hexafluoride (SF6), emitted by calibrated leak sources. As the leaked gas is heated by the laser, it expands and launches a photoacoustic sound pulse. The sound pulses generated by the scanning process are recorded across a broad bandwidth by multiple ultra-sensitive microphones. After the photoacoustic pulses arc recorded, the magnitude is compared with background noise measurement at several frequencies for a determination if a leak is present. If the presence of a leak is found, then the location of the leak is determined. The recorded sound is processed by using Matched Field Processing (MFP) as the signal processing technique.