This study has regarded the evaluation of site effects for seismic vulnerability in correspondence of a site in San Giuliano di Puglia (Italy), located in the Molise Region in Southern Italy, which is prone to high seismic risk. On October 31, 2002, a ML = 5.4 earthquake struck the Molise region in Southern Italy. The strongly non-uniform damage distribution observed in the town of San Giuliano di Puglia suggested that site amplification significantly affected the seismic response of the area. Accelerograms obtained from the recording of the aftershocks of the earthquake of October 31, 2002 have been used to evaluate the ground response analysis at the surface. Finally the 1-D computer code EERA was also used to model the equivalent-linear earthquake site response analyses of layered soil deposits. The detail with which the hill has been studied has allowed the construction of a detailed 2-D model of its structure. The difference between the computed ground motion for different Vs profiles has been explored using QUAD4M and QUAKE/W 2-D codes. It has also been possible to compare the results from different 1-D models used, reflecting current approaches to the determination of site response.