  We consider the possible formation of the quark hadron mixed phase in
protoneutron stars. We discuss two cases: the first one, corresponding to a
vanishingly small value of the surface tension of quark matter, is the well
known mixed phase in which the global electric charge neutrality condition is
imposed. In turn, this produces a non-constant pressure mixed phase. In the
second case, corresponding to very large values of the surface tension, the
charge neutrality condition holds only locally. However, the existence in
protoneutron star matter of an additional globally conserved charge, the lepton
number, allows for a new type of non-constant pressure mixed phase. We discuss
the properties of the new mixed phase and the possible effects of its formation
during the evolution of protoneutron stars.
