<p>The TOMO-ETNA experiment was devised for the investigation of the continental and oceanic crust beneath Mt. Etna volcano and northeastern Sicily up to the Aeolian Islands, through an active source study. In this experiment, a large amount of geophysical data was collected both inland and in the Ionian and Tyrrhenian Seas for identifying the major geological and structural features offshore Mt. Etna and NE Sicily. One of the oceanographic cruises organized within the TOMO-ETNA experiment was carried out on the hydrographic vessel “Galatea” by Italian Navy. During the cruise a detailed magnetic survey and a set of ROV (remotely operated vehicle) dives were performed offshore Mt. Etna. The magnetic survey allowed the compilation of a preliminary magnetic map revealing a clear direct relationship between volcanic structures and high frequency magnetic anomalies. Significant positive magnetic anomalies were identified offshore the Timpa area and along the easternmost portion of the Riposto Ridge <span>and</span> correlated to a primitive volcanic edifice and to shallow volcanic bodies, respectively. On the whole, the magnetic anomaly map highlights a clear SW-NE decreasing trend, where high amplitude positive magnetic anomaly pattern of the SW sector passes, northeastwardly, to a main negative one. ROV dives permitted to directly explore the shallowest sectors of the Riposto Ridge and to collect several videos and seafloor samples, allowing us to identify some locally developed volcanic manifestations.</p>