In the fruit fly Drosophila melanogaster, environmental light is required for maintaining long-term memory (LTM). Furthermore, the Pigment dispersing factor (Pdf), which is a circadian neuropeptide, and the neuronal activity of Pdf neurons are essential for light-dependent maintenance of courtship LTM. Since Pdf neurons can sense light directly via circadian photoreceptors [Rhodopsin 7 (Rh7) and Cryptochrome (Cry)], it is possible that Rh7 and Cry in Pdf neurons are involved in the maintenance of LTM. In this study, using a courtship conditioning assay, we demonstrated that circadian photoreceptors in Pdf neurons are required for maintaining courtship LTM.