In the SIP ““Next-generation Ocean Resource Exploration Techniques” project, various types of geophysical surveys, such as time-domain electromagnetic (TDEM), DC resistivity, self-potential, magnetic and gravity, were carried out other than seismic survey in Izena Hole, Okinawa Trough. These multimodal geophysical data give us the information of physical properties and it is required to integrate these results with seismic section to estimate seafloor massive sulfide deposits. We have developed an appropriate workflow for the quantitative interpretation as well as the 3D inversion technique for multimodal geophysical data, which incorporates known geological/geophysical constraints. Although geophysical inverse problem is generally ill-posed and unstable, a priori information can help reducing non-uniqueness and increasing stability. In the framework of our quantitative interpretation approach, the 3D inversion itself is data driven, but a priori geophysical/geological model, which is constructed using seismic and well-log data, is used as the initial and reference model during the iterative inversion process. We also have carried out rock-sampling and drilling to study the petrophysical/mineralogical characteristics. The mineralogical analysis of rock samples was performed using the quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) system. The results show that the rocks from the survey area include a large amount of sulfides. The complex resistivity measurements were performed in order to clarify the electrical properties of rocks. As expected, strong induced polarization (IP) effect was observed, mainly caused by the large amount of sulfide minerals. We have compiled these multimodal geophysical inversion results and petrophysical/mineralogical analysis to estimate the SMS deposit. There are good correlations between multimodal geophysical data and the hydrothermal deposit (e.g.. conductivity anomaly, magnetic anomaly and chargeability anomaly). Therefore, multimodal geophysical methods can be effectively used for exploration and delineation of the seafloor massive sulfide deposits.