We perform fully relativistic calculations of binary neutron stars in
quasiequilibrium circular orbits. We integrate Einstein's equations to
gether with the relativistic equation of hydrostatic equilibrium to so
lve the initial-value problem for equal-mass binaries of arbitrary sep
aration. We construct sequences of constant rest mass and identify the
innermost stable circular orbit and its angular velocity. We find tha
t the quasiequilibrium maximum allowed mass of a neutron star in a clo
se binary is slightly larger than in isolation.