In this study, transparent and flexible zinc oxide (ZnO) nanowire ultraviolet (UV) photodetectors prepared via a solution-based method in which single-walled carbon nanotube (SWNT) thin films were used as transparent electrodes are reported. The photoresponse current was found to be in proportion with the ZnO nanowire density, and the nanowire density could be tuned to increase the photocurrent by a factor of 300. The decay time for the fabricated photodetectors was found to be as low as 16 s. This study suggests the possibility of fabricating inexpensive, visible-blind UV photodetectors via solution-based methods.