  The gSeaGen code is a GENIE based application to generate neutrino-induced
events in an underwater neutrino detector. The gSeaGen code is able to generate
events induced by all neutrino flavours, taking into account topological
differences between track-type and shower-like events. The neutrino interaction
is simulated taking into account the density and the composition of the media
surrounding the detector. The main features of gSeaGen will be presented
together with some examples of its application within ANTARES and KM3NeT.
