Catathrenia is a sleep-related respiratory disorder characterizedby groaning during sleep. This situation is usually not noticed bythe affected individuals themselves but is often indicated by familymembers or bed partners. This disorder, the cause of which is notcompletely known, is extremely rare. In this case report, a patientwho admitted with a complaint of groaning and diagnosed withcatahtrenia by polysomnography was presented with its clinical andelectrophysiological features. In addition to drawing attention to the factthat catathrenia may be confused with the central sleep apnea patternin polysomnography, it was emphasized that it should be considered inthe differential diagnosis because of a limited number of cases reportedin the literature.