Three pilots simulated landfill bioreactors were used to investigate the effect of leachate injection modes on anaerobic digestion and biogas production from municipal solid waste. The technical modes used to increase waste moisture consisted of an initial saturation of the waste by flushing with leachate followed by a quick drainage, or weekly leachate injections with two different rates. The results confirmed that increasing moisture content is a key parameter to boost the biological reactions. Weekly leachate injection with high flow rate led to better results than the initial saturation of the waste in terms of biogas production kinetics. Water percolation was found to be an important factor to accelerate the degradation of solid waste. However, a modelling of the collected data by Gompertz model clearly showed that the intrinsic biogas potential determined on the initial solid waste was not reached with any of the progressive leachate injection modes. (C) 2010 Elsevier Ltd. All rights reserved.