Postoperative pain assessment in children with cognitive impairment poses major challenges to healthcare professionals.Children with moderate to severe cognitive impairment are generally unable to communicate effectively and to self-report the level of pain. Difficulties assessing pain have led to their exclusion from clinical trials and rendered them vulnerable to insufficient treatment of pain.The realization of pain is a particularly important step forward for a better care of children with cognitive impairment.Scales based on a child's own perception of pain and its severity play a limited role in this vulnerable population and pain assessment tools which rely on observing pain behavior are essential. The r-FLACC, which is reliable and valid, includes specific behavioral descriptors and can be used simply and effectively postoperatively in clinical practice. Our task has to be assessing pain as a routine procedure in cognitively impaired children as a keystone for an improved and successful pain management in this very sensitive patient population.