In the present study possibility of coupling stripper to remove ammonia to the UASB reactor treating poultry litter leachate was studied to enhance the overall performance of the reactor. UASB reactor with stripper as ammonia inhibition control mechanism exhibited better performance in terms of COD reduction (96%), methane yield (0.26 m(3) CH4/kg COD reduced), organic loading rate (OLR) (18.5 kg COD m(-3) day(-1)) and Hydraulic residence time (HRT) (12 h) compared to the UASB reactor without stripper (COD reduction: 92%: methane yield: 0.21 m(3) CH4/kg COD reduced: OUR: 13.6 kg COD m(-3) day(-1): HRT: 16 h). The improved performance was due to the reduction of total ammonia nitrogen (TAN) and free ammonia nitrogen (FAN) in the range of 75-95% and 80-95%, respectively by the use of stripper. G/L (air flow rate/poultry leachate flow rate) in the range of 60-70 and HRT in the range of 7-9 min are found to be optimum parameters for the operation of the stripper. (c) 2008 Elsevier Ltd. All rights reserved.