BACKGROUND: Delirium is a common underdiagnosed condition in advanced cancer leading to increased distress, morbidity, and mortality. Screening improves detection but there is no consensus as to the best screening tool to use with patients with advanced cancer. OBJECTIVE: To determine the incidence of delirium in patients with advanced cancer within 72 hours of admission to an acute inpatient hospice using clinical judgement and validated screening tools. METHOD: One hundred consecutive patients with advanced cancer were invited to be screened for delirium within 72 hours of admission to an acute inpatient hospice unit. Two validated tools were used, the Delirium Rating Scale-Revised 98 (DRS-R-98) and the Confusion Assessment METHOD (CAM) shortened diagnostic algorithm. These results were compared with clinical assessment by review of medical charts. RESULTS: Of 100 consecutive admissions 51 participated and of these 22 (43.1%) screened positive for delirium with CAM and/or DRS-R-98 compared to 15 (29.4%) by clinical assessment. Eleven (21.6%) were identified as hypoactive delirium and 5 (9.8%) as subsyndromal delirium. CONCLUSION: This study confirms that delirium is a common condition in patients with advanced cancer. While there remains a lack of consensus regarding the choice of delirium screening tool this study supports the CAM as being appropriate. Further research may determine the optimal screening tool for delirium enabling the development of best practice clinical guidelines for routine medical practice.