We report on the effect of ZnCdS/ZnS and ZnCdSe/ZnS core/shell quantum dots (QDs) on the efficiency of organic photovoltaic (OPV) cells. The QDs were deposited on the back side of indium tin oxide/glass substrates by spin coating with poly (methyl methacrylate). The short circuit current (J SC ) and power conversion efficiency (PCE) of the OPV cells with ZnCdS/ZnS QDs+poly(methyl methacrylate) (PMMA) (8.07mA/cm 2 and 3.2%) are higher than those of the control device without QDs (7.68mA/cm 2 and 3.0%) because the wavelength of the injected light is changed to the absorption wavelength of the active layer of the OPV cells. However, the J SC and PCE of the OPV cells with ZnCdSe/ZnS QDs+PMMA are lower than those of the control device (6.62mA/cm 2 and 2.44%) due to the low transmittance of the QDs+PMMA and discordance between the emission peak of the QDs and absorption peak of the active area in the OPV cells.