The authors' sought to develop an ultrabrief screen for postoperative delirium in cognitively intact patients older than 70 years undergoing major elective surgery. All possible combinations of one-, two- and three-item screens and their sensitivities, specificities, and 95% confidence intervals were calculated and compared with the delirium reference standard Confusion Assessment Method (CAM). Among the 560 participants (mean age, 77 years; 58% women), delirium occurred in 134 (24%). We considered 1,100 delirium assessments from postoperative days 1 and 2. The screen with the best overall performance consisted of three items: (1) Patient reports feeling confused, (2) Months of the year backward, and (3) "Does the patient appear sleepy?" with sensitivity of 92% and specificity of 72%. This brief, three-item screen rules out delirium quickly, identifies a subset of patients who require further testing, and may be an important tool to improve recognition of postoperative delirium.