The increased use of natural gas as the primary source of energy internationally, combined with the increased market price is driving the expansion and modernization of gas transportation infrastructure and is encouraging more accurate measurements of gas flows. To ensure the fair transaction at custody transfer locations, gas pipeline companies are demanding credibility and excellence of meter calibration as a main parameter in ensuring accountability for the gas invoiced. The explosive growth in the application of high accuracy ultrasonic metering technology for natural gas flow measurement has corresponded to the emphasis in the importance of accurate measurement at custody transfer points. Accurate smart metering provided by ultrasonic metering technology has lead to greater commercial confidence and has provided the opportunity for a reduction in custody transfer disputes.