We report on a search for CP violation in tau(+/-) -> K-S(0)pi(+/-)nu(tau) decays using a data sample of 699 fb(-1) collected by the Belle experiment at the KEKB electron-positron asymmetric-energy collider. The CP asymmetry is measured in four bins of the invariant mass of the K-S(0)pi(+/-) system and found to be compatible with zero with a precision of O(10(-3)) in each mass bin. Limits for the CP violation parameter Im(eta(S)) are given at the 90% confidence level. These limits are |Im(eta(S))| < 0.026 or better, depending on the parametrization used to describe the hadronic form factors, and improve upon previous limits by 1 order of magnitude.