  The energy deposition into the ejecta of type Ia supernovae is dominated at
late times by the slowing of positrons produced in the $\beta^{+}$ decays of
$^{56}$Co. Fits of model-generated light curves to observations of type Ia
supernovae suggest that a significant number of positrons escape the ejecta and
annihilate as a delayed emission. In this work, the isotopic yields of the
$\beta^{+}$ decay unstable nuclei, $^{56}$Co, $^{44}$Ti & $^{26}$Al are
combined with the delayed annihilation fractions of each isotope for types Ia,
Ib, II supernovae to generate an estimate of the positron production rate due
to supernovae. It is shown that SN produced positrons can explain a sizeable
fraction of the galactic positron annihilation radiation, as measured at 511
keV by the CGRO/OSSE, SMM and TGRS instruments.
