A two laboratory-scale aerobic sequencing batch reactors (SBR) were investigated to co-treat landfill leachate and the wastewater from industrial milk factory. The SBR reactor was operating in 24h time cycle in the following sequential operation phases: aerobic fill, aerobic react, anoxic react, settle, draw and idle. Lab-scale plant was managed by means of different operative strategies in order to find out the optimal one in terms of nitrogen compounds and COD removal. It was found that it is possible to treat combined wastewater of landfill leachate and dairy wastewater. Moreover the treatment efficiency strongly depends on operating parameters i.e. phases duration, hydraulic retention time and organic loading. The most appropriate mode for co-treatment of landfill leachate and dairy wastewater is Mode I with aeration time of 19 h and anoxic phase of 2 h. The removal efficiencies of the SBR systems decreased with increased organic loading or decreased HRT. During co-treatment process of landfill leachate the best effluent quality was observed under organic loading of 0.8 kg BOD5/m(3) d and HRT of 10 days.