We search for CP violation in the decay D+ -> (KSK+)-K-0 using a data sample with an integrated luminosity of 977 fb(-1) collected with the Belle detector at the KEKB e(+)e(-) asymmetric-energy collider. No CP violation has been observed and the CP asymmetry in D+ -> (KSK+)-K-0 decay is measured to be (-0.25 +/- 0.28 +/- 0.14)%, which is the most sensitive measurement to date.
After subtracting CP violation due to K-0 - (K) over bar (0) mixing, the CP asymmetry in D+ -> (K) over tilde K-0(+) decay is found to be (+0.08 +/- 0.28 +/- 0.14)%.