MILORD is a 3-D long-range Lagrangian particle model. Transport and dispersion of pollutants or tracers are simulated by following the trajectories of virtual particles, each representing a finite mass and/or activity of the substance considered, in a three dimensional wind field (ECMWF analyses). Diffusion due to turbulence is prescribed by integrating the Langevin equation for displacement. Depletion of the mass particle by dry and wet deposition and radioactive decay or chemical transformation are accounted for by exponential reduction equations. A post-processing analysis package allows calculating concentration and deposition over specific locations or over a grid. The model is designed to work requiring the minimum information available from typical data sets: topography, 3-D wind at standard pressure levels and precipitation. It can use any kind of gridded input data, having any time and space resolution and source configuration. It is able to treat area, line or point sources, time and space depending emissions, where a plume rise can be assigned