OBJECTIVE: To determine the incidence of perioperative delirium (POD) at the Hospital nacioanl Arzobispo Loayza, from October to December 2021.   METHODS: Qualitative and prospective observational study, carried out in a population of 910 patients, in which the AMT Test Confusion Assessment Method (CAM) and the Pfeiffer questionnaire (Short Portable Mental Status Questionnaire, SPMSQ) were applied. We used Chi2 to demonstrate the existence of association and Cramer's V and Phi tests to quantify the intensity of said relationship if it existed.   RESULTS: Of the total of patients (910), 18.46% presented perioperative delirium. Sex and religion do not influence this. Age does influence the presentation of POD since 50% (145) of the patients 61 years of age or older presented it, unlike those between 36 -60 years of age only 5.31% and those of 18 - 35 only 0.88% presented POD. According t...