  Extremely Red Objects (EROs) provide the important possibility to shed light
on the formation and evolution of the present-day massive ellipticals. On one
hand, they allow to select z>1 old passively evolving spheroidals and to
compare their abundance with the predictions of galaxy formation scenarios. On
the other hand, they provide the possibility to find dust obscured starbursts,
a fraction of which may trace the formation of proto-ellipticals at z>2. In
this paper, the most recent results on EROs are reviewed and the main
implications discussed.
