Even though stroke patients not uncommonly suffer from sleep disturbance, post-stroke sleep disorder is one of the least studied sequela of stroke, We present a case study providing polysommographic evidence for the successful alleviation of persistent insomnia in a non-depressed stroke patient by treatment with the selective serotonin reuptake inhibitor citalopram. During open treatment with citalopram the patient's sleep efficiency index improved considerably, and REM latency gradually increased. Possible causes of post-stroke insomnia are discussed, and the suggestion is made that past-stroke sleep disorder might possibly be attributable to stroke-induced disruption of pathway involved in the neurophysiology of sleep, e,g, serotonergic neurotransmission.