Abstract: Objective To observe the effect of rapid eye movement sleep deprivation (REMSD) for 5 days on depressive-like behavior and monoamine oxidase A (MAOA) expression in the amygdale of mice. Methods Adult male C57BL/6J mice were divided into blank control group, control group and REMSD group. REMSD models were established by a modified multiple small platform method. The mice were examined for locomotive activity in open field test (OFT) and for depressive-like behavior in forced swimming test (FST) and sucrose preference test (SPT) after treatment. After all the tests, the protein and mRNA expressions of MAOA in the amygdala were detected with Western blotting and real-time PCR, respectively. Results REMSD for 5 days significantly impaired the locomotive activity of the mice, which was obvious in 1 to 3 days after REMSD. The locomotive activity became normal on day 4 after the 5-day REMSD. The immobility time of the mice was lengthened in days 7 to 14 (P<0.01), and sucrose preference rate was reduced significantly in days 8 and 9 (P<0.01). The expression level of MAOA in the amygdala was increased significantly after the 5-day REMSD (P<0.01). Conclusion REMSD for 5 days causes delayed depressive-like behavior in mice possible in relation with the increased expression of MAOAin the amygdale.