The evolution of galaxies is dominated by the stellar sources (planetary nebulae and supernovae) contributing to the enrichment of the interstellar medium. The light elements are mainly due to planetary nebulae, whereas the explosive events (type II nad type I supernovae) are responsible for the elements from oxygen to nickel. Therefore, understanding the evolutionary endpoints of stars, especially supernovae, is essential in understanding the enrichment of heavy elements as function of time. Galactic chemical evolution is a global test for all contributing stellar yields; especially ejecta of supernovae (type II and type Ia).
I will discuss the nucleosynthesis occurring in the explosion of massive stars, the relevant input physics, and the uncertainties related to the complexity of core collapse supernova simulations. The nucleosynthesis yields will be confronted with recent observations of metal-poor stars and abundance trends of individual elements with metallicity.