OBJECTIVES:  Inappropriate prescribing of central nervous system and psychotropic (CNS-PS) drugs should generally be avoided in elderly population due to anticholinergic effects such as constipation, cognitive impairment and falls. This study aimed to investigate the prevalence of potentially inappropriate prescribing (PIP) of CNS-PS drugs in Korean elderly population and identify factors associated with PIP. METHODS:  We used 2013 National Aged Patient Sample data (HIRA-APS-2013), which is nationally representative data composed of 20% random sample of claims records for patients aged 65 or above enrolled in National Health Insurance or Medical Aid in 2013. Study subjects were defined as patients having at least one claim record of prescription drugs following outpatient visits from HIRA-APS-2013. PIP was determined using the CNS-PS section of Screening Tool of Older Person’s potentially inappropriate Prescriptions (STOPP) criteria version 2. RESULTS:  Among 24,427,069 prescription claims records and 1,122,080 patients included in this study, claim-level and patient-level overall PIP prevalence for CNS-PS drugs, which satisfied one or more of STOPP criteria, was 10.7% and 53.6%, respectively. The highest prevalence of PIP was observed for the criteria of ‘first-generation antihistamines’ for both of claim- (10.66%) and patient-level analysis (53.46%), followed by ‘tricyclic antidepressants (TCA) in patients with prostatism (0.03% and 0.19%)’ and ‘TCA in patients with dementia (0.03% and 0.15%).’ For indication-specific PIP, anticholinergics or antimuscarinics prescribed in patients with delirium (53.77% and 55.08% for claim- and patient-level analysis, respectively) appeared most frequent. In the logistic regression analysis, we found that PIP was strongly associated with polypharmacy (odds ratio = 4.97, 95% confidence interval: 4.94-5.00). CONCLUSIONS:  Appropriate interventions to reduce PIP should be made for the criteria that indicate high prevalence. We expect that our findings would contribute to improve the quality of prescription drug use in the elderly and consequently prevent unnecessary health care spending associated with inappropriate drug use.