Abstract: We present a new measurement of the time-dependent CP asymmetry of B-0 -> D*D+*(-) decays using (471 +/- 5) million B (B) over bar pairs collected with the BABAR detector at the PEP-II B Factory at the SLAC National Accelerator Laboratory. Using the technique of partial reconstruction, we measure the time-dependent CP asymmetry parameters S = -0.34 +/- 0.12 +/- 0.05 and C = 0.15 +/- 0.09 +/- 0.04. Using the value for the CP-odd fraction R-perpendicular to = 0.158 +/- 0.028 +/- 0.006, previously measured by BABAR with fully reconstructed B-0 -> D*D+*(-) events, we extract the CP-even components S+ = 0.49 +/- 0.18 +/- 0.07 +/- 0.04 and C+ = +0.15 +/- 0.09 +/- 0.04. In each case, the first uncertainty is statistical and the second is systematic; the third uncertainty on S+ is the contribution from the uncertainty on R-perpendicular to. The measured value of the CP-even component S+ is consistent with the value of sin2 beta measured in b -> (c (c) over bar )s transitions, and with the Standard Model expectation of small penguin contributions.