We present a new 3D SPH code which solves the general relativistic field+hydrodynamics equations in the conformally flat approximation .
Several test cases are considered to test different aspects of the code .
We finally apply then the code to the coalescence of a neutron star binary system .
The neutron stars are modeled by a polytropic equation of state ( EoS ) with adiabatic indices \Gamma = 2.0 , \Gamma = 2.6 and \Gamma = 3.0 .
We calculate the gravitational wave signals , luminosities and frequency spectra by employing the quadrupole approximation for emission and back reaction in the slow motion limit .
In addition , we consider the amount of ejected mass .