Two critically ill girls, aged 2.3 years and 3.5 years respectively, developed delirium in the Paediatric Intensive Care Unit (PICU). The first child, admitted with meningococcal meningitis and septic shock with respiratory failure, suffered from hyperactive delirium which started 2 hours post-extubation. The second child, admitted due to an exacerbation of cystic fibrosis with the threat of respiratory failure, suffered from hypoactive delirium with regression, inconsolability, dyspraxia and dysphasia. Both patients responded well to a single intravenous dose of haloperidol. Although delirium occurs in critically ill children, it often goes unrecognized, particularly in its hypoactive form. It should nevertheless be considered as a medical emergency, particularly in a PICU setting, and should be treated accordingly. Physicians are generally reluctant to consider psychopharmacological treatment of childhood delirium. Haloperidol is considered as the drug of choice, but risperidone can also be used successfully.