Several widely prescribed psychotropic medications are known to elevate the risk of postoperative delirium. In certain situations, temporarily reducing or withholding these medications before elective surgery could potentially lower this risk. However, the extent to which patients use these medications before planned surgical procedures remains unclear. This study aimed to assess the prevalence of opioid analgesics, antidepressants, gabapentinoids, and benzodiazepines used before elective surgery, to examine the frequency of delirium screening both pre- and postoperatively, and to determine the incidence of postoperative delirium among older patients taking high-risk medications. We performed a retrospective review of electronic medical records from four acute-care hospitals. Patients aged 65 years or older who underwent scheduled surgery within a two-week window were included. Data on demographics, surgical type and duration, anesthesia method, medications on admission, and 4AT delirium assessments were extracted from the records. The project was exempt from formal ethics approval under Central Adelaide Local Health Network (CALHN) Human Research Ethics Committee policy (Reference: CALHN19857), as it met the criteria for an audit, adhered to national ethical guidelines, and posed no foreseeable risk to patients. The analysis included 158 patients with a median age of 75 years. Before surgery, 41% were taking at least one medication linked to increased postoperative delirium risk: 21% were on antidepressants, 15% on opioid analgesics, 13% on benzodiazepines, and 6% on gabapentinoids. Preoperative delirium assessment with the 4AT tool was completed for 80% of participants, whereas 61% underwent at least one postoperative 4AT evaluation. A substantial proportion (41%) of older adults undergoing elective surgery were using medications associated with heightened postoperative delirium risk, yet delirium screening was not universally performed before or after surgery.