  We examine the characteristics of nucleosynthesis in 'hypernovae', i.e.,
supernovae with very large explosion energies ($ \gsim 10^{52} $ ergs). We
carry out detailed nucleosynthesis calculations for these energetic explosions
and compare the yields with those of ordinary core-collapse supernovae. We find
that both complete and incomplete Si-burning takes place over more extended,
lower density regions, so that the alpha-rich freezeout is enhanced and
produces more Ti in comparison with ordinary supernova nucleosynthesis. In
addition, oxygen and carbon burning takes place in more extended, lower density
regions than in ordinary supernovae. Therefore, the fuel elements O, C, Al are
less abundant while a larger amount of Si, S, Ar, and Ca ("Si") are synthesized
by oxygen burning; this leads to larger ratios of "Si"/O in the ejecta.
Enhancement of the mass ratio between complete and incomplete Si-burning
regions in the ejecta may explain the abundance ratios among iron-peak elements
in metal-poor stars. Also the enhanced "Si"/O ratio may explain the abundance
ratios observed in star burst galaxies. We also discuss other implications of
enhanced [Ti/Fe] and [Fe/O] for Galactic chemical evolution and the abundances
of low mass black hole binaries.
