  We report a preliminary measurement of the D0-anti-D0 mixing parameter y_CP
and the CP-violating parameter A_G using the decay D*+ -> D0 pi+ followed by D0
-> K- pi+ and D0 -> K+ K-. The results are obtained from a 158 fb^-1 data
sample collected near the Upsilon(4S) resonance with the Belle detector at the
KEKB asymmetric energy e+ e- collider.
