Cognitive deficit is caused by a variety of neurodegenerative diseases, which lead to declines in learning, memory, and concentration. Cordyceps militaris (CM) and its major component, cordycepin (CO), are attracting attention as functional food ingredients due to their beneficial health effects such as liver protection, neuroprotection, and antioxidant properties. Accordingly, this study confirmed the protective effects of CM and CO against cognitive deficits in a scopolamine-induced mouse model. CM (200 mg/kg/d) and CO (10 mg/kg/d) were orally administrated to mice for 2 weeks and behavioral experiments were conducted to confirm their effects on cognitive function. The results of T-maze and novel object recognition tests demonstrated that CM and CO were effective in improving spatial and object recognition abilities. Also the results of passive avoidance and Morris water maze tests showed that CM and CO were effective in improving short-term and long term memory abilities. Therefore, CM and CO can be considered as functional food components for improving cognitive deficits.