Disturbances of the level of awareness are a frequent motive of attendance to emergency departments where the initial assessment and management will determine the direction of their outcome. The syndrome of catatonia must be taken into consideration and although it is normally associated with psychiatric diagnoses, it is also very often found in a great variety of neurological and medical conditions. Due to the clinical complexity of catatonia, there are still difficulties in its correct identification and initial management, something that leads to diagnostic delays and increased morbidity and mortality. In this article, a review of the literature on catatonia is presented with the aim of assisting emergency department doctors (and clinicians assessing patients in emergency situations) in considering this condition in the differential diagnosis of stupor due to its high frequency of association with organic pathology.