  The measurement or constraint of the masses of neutron stars and their binary
companions tests theories of neutron star structure and of pulsar formation and
evolution. We have measured the rate of the general relativistic advance of the
longitude of periastron for the pulsar PSR B1802$-$07:
$\dot\omega=0\fdg060\pm0\fdg009\,\mbox{yr}^{-1}$, which implies a total system
mass, pulsar plus companion star, of $M=1.7\pm0.4\,\Msun$. We also present a
much improved measurement of the rate of periastron advance for PSR B2303+46:
$\dot\omega = 0\fdg0099\pm0\fdg0002\,\mbox{yr}^{-1}$, implying
$M=2.53\pm0.08\,\Msun$ for this system. We discuss the available constraints on
distribution of mass between the pulsars and their companions, and we compare
the pulsar masses with other determinations of neutron star masses.
