The effects of dye coating duration on the performance of inverted bulk heterojunction organic solar cells based on a blend of poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEHPPV) as donor and (6,6)-phenyl-C61 butyric acid methyl ester (PCBM) as acceptor with a structure of FTO/Eosin-Y coated ZnO nanorod arrays/MEHPPV:PCBM/Au utilizing ZnO nanorod arrays as electron collecting layer and gold as a hole collecting electrode were investigated. ZnO nanorod arrays were grown on fluorine-doped tin oxide (FTO) glass substrates which were pre-coated with ZnO nanoparticles using a low temperature chemical solution method. The ZnO nanorods-coated FTO substrates were immersed in the Eosin-Y dye solution at 60 oC for 15, 60 and 120 min. The power conversion efficiency of the solar cell increased with dye coating duration and reached an optimum value at dye coating duration of 60 min. The device with dye coating duration of 60 min exhibited the highest power conversion efficiency of 5.05 x 10-4 % with short circuit current density of 9.95 μA/cm2, open circuit voltage of 0.18 V and fill factor of 28%.