The co-treatment of sewage and landfill leachate in wastewater treatment plants has proved to be a promising alternative for the integrated management of these effluents. This study evaluated the performance of the moving bed biofilm reactor (MBBR) process in the treatment of sanitary sewage with the addition of 1 per cent (v/v) landfill leachate, using a filling fraction of 30 per cent biomedia. The study was conducted on a bench scale with two identical MBBR reactors simultaneously operated for 292 days. The control reactor (R1) received only synthetic sewage, while the test reactor (R2) received synthetic sewage with the addition of 1 per cent leachate. The reactors were operated with an average hydraulic detention time of 10.5 hours and monitored for the removal of organic matter, nutrients and other quality parameters. The MBBR process showed satisfactory efficiency in the treatment of sanitary sewage, achieving average removals of 81.0 per cent for COD and 70.6 per cent for COD in reactor R1. The addition of 1 per cent leachate did not significantly compromise the performance of the process, with reactor R2 showing average removals of 80.5 per cent for COD and 71.2 per cent for COD. The excess sludge was significantly higher in R2 (1.17 gSVdia-1) compared to R1 (0.63 gSVdia-1), but there was no significant difference in the concentration of solids adhered to the biomedia between the reactors. The results obtained demonstrate that the MBBR process is a viable alternative for co-treating sanitary sewage and landfill leachate, with satisfactory removal efficiencies even with the addition of leachate and a low concentration of adhered solids.