The impact behaviour of composite geo-cells used as components of rock fall protection structures is studied experimentally. The response of single cells subjected to impact by a boulder vertically dropped with energies of 13.5kJ is analysed. The influence of the cell filling material and cell boundary conditions is discussed. The damping potential of an impacted cell appears to depend on these two conditions. Experimental results are then compared with numerical ones obtained using the discrete element method -DEM.