  Recent results by the NA48 collaboration on neutral kaons rare decays into
the pi+ pi- e+ e- final state are presented. A large CP-violating asymmetry
A(K_L)=(13.9+-2.7+-2.0)% has been observed in the K_L to pi+ pi- e+ e- decay.
The K_S to pi+ pi- e+ e- decay has been observed for the first time, showing no
such asymmetry.
