Mt. Etna is one of the most fascinating natural laboratories for studying the deep structure of an active volcano with seismic tomography. Mt. Etna's eruptive dynamics are the result of a complex interaction between magma in its plumbing system, the regional (deep crust) tectonic regime, and local (shallow crust; volcanic edifice) structures, partially controlled by flank instability. Magma ascent driving conditions (e.g., structural setting, tectonic forces) are not yet completely understood. One of the main limitations in understanding the volcano's eruptive dynamics is the insufficient knowledge of its intermediate and deep crust. As indicated in Ibáñez et al. [2016, in this volume] in the last 25 years, several seismic and tomographic experiments have been focused on the study of Mt. Etna's structure using different techniques and **data** sets. The TOMO-ETNA experiment is an international and multi-institutional joint effort focused into providing answers to some of the open questions associated to the structure and dynamics of Mt. Etna. This experiment will take advantage of the use of both active and passive seismic sources and the combination of information of other seismic and geophysics measurements such as marine seismic reflection [Coltelli et al. 2016, in this volume;Firetto Carlino et al. 2016, in this volume] or magnetic profiles [Cavallaro et al. 2016, in this volume].