Neutrinos and the Universe

In this talk, I review the potential connection of neutrinos to the Physics of the Early Universe, in particular the r\^ole of (sterile) neutrinos to leptogenesis/baryogenesis and the dark sector of the Universe. The possibility of CPT Violation among active neutrinos at early times and its role in leptogenesis/baryogenesis without sterile neutrinos is also touched upon.