The palmomental reflex is a well-known neurologic sign, however its current diagnostic value is considered limited and its role in the neurologic examination has been questioned. Given that a century has passed since its first description in 1920, we conducted a review of the literature about the palmomental reflex, beginning with its physiology and prevalence in the general population, and continuing with its possible diagnostic and prognostic value in relation to neurologic disorders such as dementia, Parkinson disease, amyotrophic lateral sclerosis, stroke and frontal lobe disease.