Objective: In the present study, the effects of aqueous saffron extract (Crocus sativus L.) on the acquisition and reinstatement of morphine-induced conditioned place preference (CPP) in mice were investigated. Materials and Methods: Subcutaneous administration of morphine (40 mg/kg for four days) produced place preference. Intraperitoneal administration of aqueous extract (40 and 80 mg/kg for four days) 30 min before the morphine administration decreased the acquisition of morphine CPP. In other groups of animal, following extinction of a place preference induced by morphine (40 mg/kg), single administration of morphine (10 mg/kg) reinstated the place reference. The aqueous extract (80 mg/kg) 30 min before this priming dose of morphine blocked morphine-induced reinstatement of place preference. Results: These results show that aqueous saffron extract can reduce the acquisition and reinstatement of morphine-induced conditioned place preference.