  The observed cosmic gamma-ray background at ~ MeV has often been attributed
to Type Ia supernovae (SNIa). Since SNIa is close to a standard candle, one can
calculate the gamma-ray intensity of SNIa integrated over redshifts fairly
accurately, once the evolution of the SNIa rate is known. The latest SNIa rate
measured at z < ~1.6 (Dahlen et al. 2004) indicates that the previous
calculations of the gamma-ray background consistently overestimated the SNIa
rate. With the new rate, we find that the SNIa contribution is an order of
magnitude smaller than observed, and thus new population(s) of sources should
be invoked.
