The C-odd exchange in hadronic reactions with rapidity gaps is described
by the Odderon but its experimental evidence is still weak since the
C-even exchange (the Pomeron) dominates. In this talk I will present a
possibility to observe the Odderon by interference effects with the
Pomeron in charge asymmetries in the production of two pion pairs. After
the discussion of the theoretical framework for our calculation based on
high energy factorization and the necessary phenomenological input, the
calculation of the charge asymmetry and its result will be presented.