Submerged membrane bioreactor (MBR) technology for aerobic treatment of landfill leachate was studied in laboratory scale to evaluate its potential for on-site use. Three combinations of solid retention time (SRT) - hydraulic retention time (HRT) of 60 days - 3.5 days, 60 days - 2 days and 30 days - 1 day, were examined to evaluate reactor performance under varying loading and biomass conditions. Chemical Oxygen Demand (COD) removal ranged from 54 to 78%, depending on the influent leachate source and loading conditions. The MBR showed excellent Biological Oxygen Demand (BOD5) removal of 97% and higher, even at HRT as low as 1 day. Complete suspended solids retention and full nitrification of the incoming ammonia was observed despite highly variable loading. Significant removal of iron, lead, manganese, cadmium and aluminum was observed. No significant changes in the removal efficiency of metals, ammonia, and BOD5 were observed at different SRT-HRT. Toxicity removal decreased with increasing HRT. The produced effluent met current water quality guidelines for discharge into natural streams in Manitoba.