The chapter discusses the evaluation of metal–organic frameworks (MOFs) for natural gas storage, highlighting the challenges in comparing high-pressure adsorption data and the lack of comparative studies. It reviews efforts to develop MOFs with high methane storage capacities and evaluates six MOFs and an activated carbon in detail. The evaluation focuses on gravimetric and volumetric capacities, isosteric heats of adsorption, and usable storage capacities. The importance of increasing volumetric capacity over gravimetric capacity for extending the driving range of natural gas vehicles is emphasized. Other factors such as thermal management, mechanical properties, and impurities are also considered. The chapter provides recommendations for future evaluations of new MOFs and discusses the fundamental mechanisms behind the high volumetric uptakes of Ni2(dobdc) and HKUST-1. It concludes by emphasizing the relative importance of improving volumetric capacity over gravimetric capacity for enhancing the practicality of natural gas vehicles.The chapter discusses the evaluation of metal–organic frameworks (MOFs) for natural gas storage, highlighting the challenges in comparing high-pressure adsorption data and the lack of comparative studies. It reviews efforts to develop MOFs with high methane storage capacities and evaluates six MOFs and an activated carbon in detail. The evaluation focuses on gravimetric and volumetric capacities, isosteric heats of adsorption, and usable storage capacities. The importance of increasing volumetric capacity over gravimetric capacity for extending the driving range of natural gas vehicles is emphasized. Other factors such as thermal management, mechanical properties, and impurities are also considered. The chapter provides recommendations for future evaluations of new MOFs and discusses the fundamental mechanisms behind the high volumetric uptakes of Ni2(dobdc) and HKUST-1. It concludes by emphasizing the relative importance of improving volumetric capacity over gravimetric capacity for enhancing the practicality of natural gas vehicles.