Background: Few studies have been done considering the effectiveness of aqueous extract of cinnamon in neurological diseases. In previous studies, reducing the pain of hydro-alcoholic cinnamon extract in the second phase (chronic) of the formalin test and reduction of inflammation in animal models as well as in humans following cinnamon administration have been emphasized. There are also studies on the anti-Alzheimer's effects of this extract. However, the effects of CWE of this plant on the incidence of diseases associated with the nervous system, especially depression, have not been investigated.Objective: In the present study, the effects of CWE on depression induced by forced swimming test (FST) in mice were investigated. Methods: Cinnamon aqueous extract was obtained by boiling method of cinnamon powder. Male NMRI mice (25-30 g) were used (n=8/group). Different doses of CWE (25, 50, 100, and 200 mg/kg) were administered intraperitoneally to the animals 30 min before the (FST). In addition, fluoxetine (20 mg/kg) was administered to distinct animals as positive control.Results: Intraperitoneal (50, 100, and 200 mg/kg) injections of CWE significantly reduced the animals' immobilization in a dose-dependent manner which in doses of 100 and 200 mg/kg was similar to fluoxetine effect. Conclusion: It could be concluded that the CWE can inhibit depression induced by FST in mice.Since the exact composition of the extract is not identified, the exact mechanism(s) by which the extract reduces the FST is not clear.