Background and Objectives: Serotonergic system has a role in procedure of morphine dependence and withdrawal signs incidence. On the other hand it has been shown that antidepressants may reduce the abuse susceptibility of opioids. So, the aim of this study was to investigate the effect of citalopram as a selective serotonin reuptake inhibitor (SSRIs) antidepressant on morphine withdrawal signs in male mice.Materials and Methods: In this experimental study forty male NMRI mice (20-30 g) were used. Morphine dependency was induced using a four- day schedule method with 50, 50, 75 and 50 mg/kg dosing respectively.In the fourth day 2 hours after single dose of morphine, naloxone was injected (5 mg/kg) and withdrawal signs were recorded with number of jumping and diarrhea, grooming, wet dog shake, teeth chattering, writing, climbing based on the scores of 0 to 3 for 30min.Treatment group received different doses of citalopram (5, 10 and 20 mg/kg; Intraperitoneally).Results: Different doses of citalopram dose-dependently and significantly decreased the morphine withdrawal signs (except diarrhea) in the experimental group (p<0.05 and p<0.001).Conclusion: The present study is in accordance with other reports indicated that 5-HT enhancing agents (e.g. SSRIs) may be promising treatments for morphine withdrawal signs.