  The Ep,i - Eiso correlation is one of the most intriguing and debated
observational evidences in Gamma-Ray Bursts (GRB) astrophysics. Swift, with its
high sensitivity and fast pointing capabilities, is reducing a lot the impact
of selection effects in the sample of GRBs with known redshift (and thus Ep,i
and Eiso). Moreover, in several cases it allows the detection of the soft tail
of the prompt emission, and thus a more accurate estimate of Ep,i with respect
to previous satellites. I present and discuss the location in the Ep,i - Eiso
plane of Swift GRBs with known redshift and estimated Ep,i, showing that all
long events (including peculiar events like GRB060218 and GRB060614) are
consistent with the Ep,i - Eiso correlation. In contrast, short GRBs are not
consistent with it, an evidence further supporting the hypothesis of different
emission mechanisms at work in the two classes of GRBs. I also show, and
briefly discuss, the intriguing evidence that the soft tail of the short
GRB050724 is consistent with the correlation.
