  We calculate evolution and nucleosynthesis in massive Pop III stars with M =
13 ~ 270Msun, and compare the results with abundances of very metal-poor halo
stars. The observed abundances can be explained by the energetic core-collapse
supernovae with M < ~ 130Msun (``hypernovae'') but not by pair-instability
supernovae (PISNe) with M ~ 140-270 Msun. This result constrain the IMF for the
Pop III and very metal-poor Pop II stars.
