  In this paper we study the final fate of the universe in modified theories of
gravity. As compared with general relativistic formulations, in these scenarios
the Friedmann equation has additional terms which are relevant for low density
epochs. We analyze the sort of future singularities to be found under the usual
assumption the expanding Universe is solely filled with a pressureless
component. We report our results using two schemes: one concerned with the
behavior of curvature scalars, and a more refined one linked to observers. Some
examples with a very solid theoretical motivation and some others with a more
phenomenological nature are used for illustration.
