Background: Melatonin receptors are detected in human skin as well as retina of the eye. Light-emitting diodes (LEDs), which can stimulate melatonin receptors, at specific wavelengths are known to induce cutaneous rejuvenation. Objectives: To evaluate the influence of LEDs at specific wavelengths on melatonin membrane receptor (MT1) and cutaneous photorejuvenation via the MT1 pathway, in vitro Methods: .Normal human dermal fibroblasts (HDFs) were irradiated by LEDs at different wavelengths and at a dose of 1 J/㎠. First, the activities of MT1 were evaluated after melatonin and LED stimulation, respectively. Second, the expressions of collagen (COL) and matrix metalloproteinases (MMPs) after melatonin and LED stimulation, respectively, with and without luzindole (MT1/2 receptor antagonist), were investigated Results: mRNA and protein levels of MT1 significantly increased in response to melatonin and LED at 580, 595, 630, 850, and 940 nm. mRNA and protein levels of COL type I were up-regulated while those of MMP-1 were down-regulated in response to LED irradiation at 595, 630, and 940 nm. When luzindole was combined with LED irradiation, there were no significant increases of mRNA and protein levels of COL type I. Conclusion: Our study revealed that LED with specific wavelength showed significant collagen synthesis and MMP-1 inhibition, which were conducted via MT1 activation. This suggests that melatoninergic response to light of the human skin may be distinct from that of the ocular route.