Rockfall protection systems are installed in order to preserve civil infrastructures against landslides and falling rocks. For the evaluation of these systems,one of the main problems is the difficulty to develop laboratory tests, since landslides and falling rocks are unpredictable events that involve the movement of large masses of material over several meters or evenkil-ometers. For this reason, the use of numerical methods, which allows reproducing full-scale situations without the need of laboratory devices or sliding materials, has become more popular. The study presented in this document shows theapplication of the Discrete Element Method (DEM) for the analysis of the behavior of one of the most popular rockfall protection systems, flexible metallic fences.