Postoperative delirium is a neuropsychiatric disorder characterized by abnormal behaviors following surgery, including disorientation, delusions, and hallucinations. This study preoperatively assessed predisposing factors for delirium and examined its postoperative symptoms and treatments. A total of 71 patients who underwent general anesthesia were included. Delirium assessment sheets from the DELirium Team Approach (DELTA) program were used for delirium evaluation. Postoperative delirium was observed in 17 cases. Patients were divided into two groups: those with postoperative delirium symptoms (delirium group) and those without (non-delirium), and their predisposing factors were compared. The delirium group had a significantly higher proportion of patients aged 70 years or older, as well as patients with organic brain disorders and coexisting dementia. The mean age was significantly higher in the delirium group (78.5 years) compared to the non-delirium group (69.4 years). No significant differences were observed between the two groups in operative time, duration of anesthesia, blood loss, or transfusion volume. Delirium symptoms in the delirium group included inattention in 15 cases, disorganized thinking in 8 cases, and altered levels of consciousness in 6 cases. Treatments included physical restraints in 15 cases, administration of antipsychotic medications in 10 cases, and use of sedative-hypnotics in 4 cases. Particular attention should be given to the risk of postoperative delirium, especially in surgical patients aged 70 or older and those with organic brain disorders.