Summary Introduction: Delirium is a common disorder that can potentiate mortality and comorbidity rates of patients hospitalized in intensive care units. Patients undergoing major orthopedic surgeries, such as knee and hip arthroplasty, are particularly vulnerable as they often have multiple risk factors for this disorder. Method: Descriptive study of the incidence of delirium in patients treated with total knee and hip arthroplasty, given the advanced age and comorbidities in this population. We evaluated the medical records of patients who had previously undergone the designated surgeries for identification of postoperative delirium. Results: We observed in this study an incidence of 8.92% of delirium, mostly affecting females with a mean age of 73 years and hypertension. Conclusion: The incidence of delirium in our study is similar to that observed in the general population, according to the literature. We found no correlation with sleep disorders, smoking or diabetes mellitus in this study, even though the importance of these factors for the onset of delirium is well-established in the literature.