Development of an Excavation Damaged Zone around an underground excavation can change the physical, mechanical and hydraulic behaviours of the rock mass near the underground space. This paper presents an approach to build a prediction model for the assessment of EDZ based on an artificial intelligence method called artificial neural networks which are applied to build a prediction model for the assessment of EDZ using data of geological and blasting parameters which are chosen as a result of a literature review. Upon developing the model to evaluate rock damage from underground blasts, practical applications were accomplished for confirmation. Results showed that, because of their high accuracy in establishment of a correlation between EDZ and input parameters' data, ANNs are appropriate tools to predict excavation damaged zone using data of parameters including perimeter powder factor, rock mass quality, tensile strength, density, wave velocity, vibration propagation coefficients and explosive detonated per delay. 1 INTRODUCTION The extent of excavation damaged zone depends on geological structure, excavation method, overburden, and numerous other parameters. Prediction of this damage is an important factor to evaluate the quality of excavation process in tunnelling and underground mining. It would allow the optimization of explosive charges utilized in successive blasting rounds, as well as lowering risks of instability from rock loosening, less support costs and water inflows. The detonation of explosives confined in boreholes generates a large volume of gases at high pressures and temperatures. The sudden application of these effects to the cylindrical surface of the hole generates a compressive stress pulse in the rock, which may be a source of damage in the surrounding zone. The dimensions of that zone depend on the size of explosive charge detonated, rock's dynamic strength and density, wave velocity propagation, and vibration velocities transmitted to the rock mass. The detonation of explosives confined in boreholes generates a large volume of gases at high temperatures (2000–5000°C) and high pressures (10–40 GPa). The sudden application of these effects to the cylindrical surface of the hole generates a compressive stress pulse in the rock, which may be a source of damage in the surrounding zone. These deviations are normally undesirable because they generate higher costs in the constructive process of the underground opening [Dinis Da Gama, et al., 2002].