In this contribution we present results of the MM5-CMAQ Modelling System which has been implemented over LINUX-PC to run in operational mode over Madrid City. The model has been setup over the Iberian Peninsula domain for MM5 mother domain and three nesting levels up to 1 km grid resolution over the city of Madrid (30 x 30 km). The CMAQ EPA-Models-3 Community Multiscale Air Quality Modeling System has been set up over two model domains: mother domain with 3 km grid cell resolution and nesting level 1 over Madrid city (30 x 30 km) with 1 km spatial resolution. The system has been running in operational mode over two months. Results show a good agreement between PM observational and modelling data. The system seems to be very robust and feasible for air quality urban forecasting in operational mode.