Abstract: Aim of this study was to compare the effect of monochromatic light on transcription of melanopsin(OPN4-1 and OPN4-2), green sensitive cone opsin (CHK-1) and blue sensitive cone opsin (CHK-2) genes in the retinas and pineal glands of broiler. Forty newly hatched male AA (Arbor Acres) broilers were exposed to white (400-760 nm), red (660 nm), green (560 nm) and blue light (480 nm) for 14 days by using LED (light-emitting diodes) with 15 lx light intensity as light sources, respectively. The total RNA of retinas and pineal glands was extracted respectively on the 14th day. After reverse transcription, PCR amplification was carried out to detect transcription of above four opsin-related genes by using corresponding primers. The results showed:(1)OPN4-1 mRNA expression of BL group were 13.44% and 16.77% higher than that of WL group either in the retinas or pineal glands (P<0.05) significantly, but OPN4-1 mRNA expression of RL and GL groups were 16.62% and 10.94% lower than that of WL group in the retinas (P<0.05) significantly and no significant difference was detected between GL and WL groups in the pineal glands (P>0.05).(2)In the retinas and pineal glands, OPN4-2 mRNA expression of RL group was the highest, followed by BL group, and GL group was the lowest in all light groups (P<0.05).(3)In the retinas, the expression of CHK-1 mRNA was higher than that of CHK-2 under four monochromatic lights. CHK-1 mRNA expression of GL group was 24.37% and 9.94% higher than that of RL and BL groups (P<0.05) and no significant difference was found between GL and WL groups (P>0.05). CHK-2 mRNA expression of BL group were 40.90% and 8.94% higher-than that of RL and GL groups (P<0.05) and no significant difference was found between BL and WL groups (P>0.05). Above results suggested that the different opsins have the different light color sensitivity. Compare to red and green light, blue light promote the transcription of OPN4-1 in the retinas and pineal glands.