Prospects for the phased anaerobic treatment of wastewater are extremely promising. With the variety of reactor designs available and the amenability of reactors to modification, existing treatment systems may be replaced or upgraded as required to achieve increased stability, higher loading capacities and greater process efficiencies than single-stage systems. In recent times, various reactor configurations and substrates are applied to two-phase anaerobic process. This paper reviews applications and studies of two-phase anaerobic degradation for wastewater treatment, sums up the performance of application to treating waste from distillery, landfill leachate, coffee, cheese whey and dairy, food, pulp and paper, sludge and solid, etc., and summarises reactor configurations, environmental and operational conditions, and comparisons of two-phase anaerobic digestion with other anaerobic reactors.