Several studies have been shown that morphine affects the learning and memory processes. Systemic and central administrations of morphine impair learning and memory in the different models of memory. The central amygdala (CeA) plays a critical role in expression of emotions and memory consolidation. Considering these reports indicate the existence of the cholinergic receptors in the CeA and the interactions between cholinergic and opioid systems in memory formation. In this study, we examined the effect of pilocarpine (cholinergic muscarinic receptors agonist) on morphine-induced amnesia in adult male Wistar rats. Long-term memory of the animals was evaluated by step-through type passive avoidance task in two-step (train and test with 24 h interval), a week after surgery and bilaterally implantation of cannulas in the CeA. Retention measured by step-through latencies. Results indicate that post-training subcutaneous administration of morphine (2.5-7.5mg/kg) dose-dependently decreased the step-through latency, and induced amnesia. Pilocarpine (0.5-1.5μg/rat, intra-CeA) increased the step-through latency and inhibited of morphine-induced amnesia. Moreover, pilocarpine did not alone effect on memory retrieval. The existing evidence supports that morphine dose-dependently impairs retention of memory and thus exerts amnesic effect in passive avoidance memory. Moreover, the results suggest a possible role for muscarinic acetylcholine receptors of the central amygdala nuclei in the improving effect of pilocarpine on the morphine –induced amnesia.