Delirium in advanced cancer is often poorly identified and inappropriately managed. It is one of the most common causes for admission to clinical institutions and is the most frequently cited psychiatric disorder in terminal cancer. Diagnosis of delirium is defined as a disturbance of consciousness and attention with a change in cognition and/or perception. In addition, it develops suddenly and follows a fluctuating course and it is related to other causes, such as cancer, metabolic disorders or the effects of drugs. Delirium occurs in 26% to 44% of cancer patients admitted to hospital or hospice. Of all advanced cancer patients, over 80% eventually experience delirium in their final days. In advanced cancer, delirium is a multifactorial syndrome where opioids factor in almost 60% of episodes. Delirium in such patients, excluding terminal delirium, may be reversible in 50% of cases. Providing adequate end-of-life care for a patient with delirium is the main challenge. The family needs advice and it is important to create a relaxing environment for the patient. The primary therapeutic approach is to identify the reversible causes of delirium. Some therapeutic strategies have been shown to be effective: reduction or withdrawal of the psychoactive medication, opioid rotation, and hydration. Haloperidol is the most frequently used drug, and new neuroleptics such as risperidone or olanzapine are being tested with good results. Methylphenidate has been used for hypoactive delirium.