Gas content measurement has a significant impact on mine safety and operational efficiency at many Australian underground coal mines. There is an expectation that reported gas content results are accurate and correctly represent the gas content of the coal seam in the area where the coal samples were collected. The practice of some coal sample testing service providers to add ‘correction’ factors to the measured gas content of coal samples increases the reported gas content to account for assumed loss of gas content due to extended recovery time. The methodology used by one gas testing service provider to establish a gas content correction factor to apply to coal samples with extended recovery time has been investigated and discussed. A new approach to testing the impact of extended core sample recovery time on the accuracy of gas content measurement has been developed and is presented. Initial results from testing at three Australian underground coal mines indicates that, for core sample recovery times extending to 180 minutes, there is no discernible loss of gas content that would warrant the addition of a ‘correction factor’.