In this letter, we report on an efficient organic tandem solar cell combining a solid state dye-sensitized with a ZnPC/C(60)-based, vacuum deposited bulk heterojunction solar cell. Due to an effective serial connection of both subcells and to the complementary absorption of the dyes used, a power conversion efficiency of eta(p) = (6.0 +/- 0.1)% was achieved under simulated 100 mW/cm(2) AM 1.5 illumination. The device parameters are V(oc) = (1360 +/- 10) mV, I(sc) = (8.2 +/- 0.1) mA/cm(2) and FF = (54 +/- 1)%. (C) 2009 Elsevier B.V. All rights reserved.