Three bituminous coal samples, from Salt Range, Makarwal, and Khost coalfields of Pakistan, were subjected to a bioassay, based on WBC-2, for determining the potential of biogenic methane generation from higher-rank coals. Under strict anerobic conditions, maximum methane yield was observed from Makarwal coal sample, that is, 0.275 mu moles per gram of coal. The results supported the idea of inhibited susceptibility of higher-rank coal toward biogenic methane generation. Low-rank coal still appears as a favorable target for stimulation or regeneration of methane, though, before achieving commercial-scale methane generation, there are a number of crucial factors, which need to be addressed.