Anaerobic MBRs (AnMBRs) have been shown to be one of the most promising technologies for sustainable wastewater treatment. It offers several advantages over the aerobic MBRs, namely, requirement of no energy for aeration, low sludge production and energy resource. Compared to the conventional anaerobic processes, AnMBRs can maintain higher biomass concentrations, have higher treatment capacity, excellent effluent quality, and smaller footprint. Compared with the conventional anaerobic digestion, they are relatively robust to cope with variations in organic loading and inhibitory conditions due to complete retention of biomass by membranes. The AnMBR technology is now gaining acceptance by a wide range of industries. The achievements of AnMBRs in pilotscale studies and full-scale applications are surveyed in this chapter. Lab- and pilot-scale studies provide important information to scale up AnMBRs and upgrade the existing anaerobic process into full-scale AnMBR systems. However, membrane fouling is still the major issue limiting its popularity and development in commercialization. The factors affecting the treatment performance and membrane fouling are reviewed along with an in depth discussion of fouling mechanisms, characteristics and control strategies. Moreover, an overview of its commercial potential in water reuse, energy production, and costs of AnMBRs in wastewater treatments is covered. The combination of AnMBRs and other effluent polishing treatments is desirable for the purpose of water reuse. Meanwhile, it is appealing to take advantage of the biogas produced as an energy resource. The lower total cost of AnMBR than that of aerobic MBRs shows its economic feasibility. Finally, the research needs for future developments are summarized based on the state-of-the-art of AnMBR technology.