Stress represents a wide range of physical responses and plays an important role in modulating different stages of memory including reconsolidation. Relapse to drug taking induced by exposure to stimuli or cues associated with drugs of abuse is a main challenge to the treatment of morphine addiction. It has been shown that drug seeking can be inhibited by disrupting the reconsolidation of a drug-related memory, but, the effect of glucocorticoid receptors in Basolateral Amygdala on the alteration in morphine-induced conditioned place preference following swim stress has not been fully studied. We examined the effects of forced swim stress (FFS) and corticosterone on reconsolidation of a drug-related memory using a conditioned place preference (CPP) procedure. Male adult rats received FSS as a physical stress or corticosterone (10 mg/kg; ip) as a dominant stress hormone in rodents, 10 min before injection of morphine (5 mg/kg; sc), during 3 conditioning days (acquisition) or just prior to CPP test in the post-conditioning day (expression). In FSS procedure, animals were forced to swim for 6 min in cylinder filled with water (24-27 οC). All animals underwent extinction sessions until the CPP was extinguished; rats were confined to the previous morphine- or saline-paired compartment for 30 min a day for 8 days. The next day following the last extinction session, morphine CPP reinstatement was induced by FSS as stress-induced reinstatement. The results showed that animals acquired morphine CPP after conditioning, and that this CPP was inhibited by stress given immediately after re-exposure to morphine. Corticosterone injection which leads to immediate and sudden increase in the level of glucocorticoids fails to reinstate the terminated CPP in rats. Studies on FSS-induced reinstatement show that this behavior is blocked by administration of corticotropin-releasing hormone (CRH) antagonists. Overall, these results suggest that corticosterone plays an important role in relapse to drug seeking behavior induced by stress.