All the geological and geophysical data available for NE Italy, area of high seismicity, have been updated and reciprocally compared to identify seismotectonically homogeneous zones. Neotectonic and seismic activities are relevant especially at the interaction between the Southalpine Chain and the External Dinaric one. The obtained result consists in the definition of 4 megaunits, which are the first sketch of the regional seismotectonic model, basis for hazard zoning.-Authors Osservatorio Geofisico Sperimentale di Trieste, Italy.