This study was conducted to evaluate the performance of biological treatment plant of a brewery located at Rajasthan, India. The biological treatment consists of anaerobic treatment through anaerobic hybrid reactor (AHR) and conventional aerobic treatment (Activated Sludge Process (ASP)). The results showed that the COD removal efficiencies ranged between 46.96 % -89.71% for anaerobic treatment at an Organic Loading Rate of 0.9 -3.6 kg COD/ m3/day. The COD removal efficiency after aeration was in range of 12% to 74%, making overall removal efficiencies of COD after Anaerobic (AHR) and Aerobic system to be between 75% to 97%. This paper includes effluent characterization, treatment scheme and performance of a brewery ETP under study. In addition to it, the problems associated with the operation and maintenance of brewery Effluent Treatment Plant was discussed and suitable recommendations were made based on its performance.