Sleep Paralysis is the persistence of REM atonia into the wakefulness. It is found in normal subjects, but is frequently seen in narcolepsy, in conjunction with hypnogogic hallucinations and cataplexy. We investigated whether sleep paralysis may be associated with sleep disorders other than narcolepsy. A retrospective review of all patients seen at St Thomas' Sleep Disorders Centre over a 9-year period was undertaken looking for sleep paralysis as a presenting symptom. In total, 15 patients were identified who presented with sleep paralysis without other features of narcolepsy. Three had a family history of isolated sleep paralysis, five had isolated sleep paralysis without family history, and seven were found to have episodes of desaturation or apnoea in REM sleep on polysomnography. Treatment with oral appliances, CPAP or ENT surgery resulted in resolution in sleep paralysis symptoms in three patients, and in one patient weight loss alone caused improvement. None were subsequently diagnosed with narcolepsy. Sleep paralysis can be isolated or in associated with narcolepsy, but it can be the presenting symptom of OSA. In this situation appropriate treatment of OSA may lead to resolution of the sleep paralysis. Isolated sleep paralysis does not appear to be a presentation of narcolepsy.