We report a measurement of time-dependent CP violation in B-0 -> K-S(0)pi(0)pi(0) decays using a data sample of 772 x 10(6) B (B) over bar pairs collected by the Belle experiment running at the (sic)(4S) resonance at the KEKB e(+)e(-) collider. This decay proceeds mainly via a b -> sd (d) triple over dot "penguin" amplitude.
The results are sin 2 phi(eff)(1) = 0.92(-0.31)(+0.27) (stat.) +/- 0.11 (syst.) and A = 0.28 +/- 0.21 (stat.) +/- 0.04 (syst.), which are the most precise measurements of CP violation in this decay mode to date. The value for the CP-violating parameter sin 2 phi(eff)(1) is consistent with that obtained using decay modes proceeding via a b -> c (c) over bars "tree" amplitude.