The European-Mediterranean Regional Centroid Moment Tensor (RCMT) Catalog collects seismic moment tensor solutions that have been routinely computed since 1997 for earthquakes with moderate magnitude (4.5 < M < 5.5) in the Mediterranean region. This database represents an extension to smaller magnitudes of the Global CMT catalog (http://www.globalcmt.org). RCMT computation is based on analysis of seismograms recorded at regional distances, and modeling of intermediate period surface waves. The Catalog is regularly updated a few months behind real time, and reports are published in Phys. Earth Planet. Int. and on the worldwide web (http://www.bo.ingv.it/RCMT). However, moment tensors can also be computed on the basis of data available in quasi-real time. Such preliminary solutions are available within one or a few hours after an earthquake occurs, and published as a Quick RCMTs. The European-Mediterranean RCMT Catalog currently includes more than 800 seismic moment tensor solutions, mainly located in the most seismically active areas, such as northern Greece and the Hellenic trench. The database is a valuable complement to Global CMTs for tectonic studies. We show results from regions of special interest — such as the Dead sea, the Cyprus region and the Adriatic sea — and discuss the seismotectonics. Seismic deformation in these regions was previously poorly documented, mainly because the fact that previous catalogs of source mechanisms were limited to greater magnitude seismicity.