The creepy snap seems to show a ghoulish face in shadows on the first-floor window of the former psychiatric hospital - despite it being closed for 15 years.
The asylum in Bronllys, Brecon, Wales, was also a Prisoner of War camp in World War Two where captured German soldiers were kept.
After the war it housed psychiatric patients who were sometimes lobotomised for conditions like postnatal depression, alcoholism and senile dementia.
At least one patient is known to have died on the site from a pre-frontal lobotomy which saw part of the brain damaged by cracking open the skull and severing nerves.
The spooky image was taken by walker Adam Smith as he strolled past the outside of the crumbling, moss-covered building.
He said: "I caught an epic shot of a ghost at the abandoned Brecon and Radnor Lunatic Asylum.
"Maybe it was a patient who had a lobotomy or perhaps a soldier patient from the war or maybe a Nazi prisoner.
"Whatever it was, it certainly gave me a fright."
Read Full Stroy: Mirror UK
Ghost of former patient appears in a abandoned asylum window
Tags :
Brecon and Radnor Lunatic Asylum,
Bronylls,
Ghost,
Haunted,
Paranormal,
Wales
Related : Ghost of former patient appears in a abandoned asylum window
Did a security camera capture a ghost playing in the street (video) A man is in shock after capturing spooky CCTV footage of a ghost in the road outside his home in Abbey Wood. Ian Hawke, 42, of Overton Road, was sitting down and lo ... 
Gamer Live Streams some freaky Paranormal Activity experience (video)Everything seemed normal for a YouTuber known as "Rubzy" one night last November. However, things would get very strange very quickly for the young gamer. While pet s ... 
Ghost Comes Home with Son and Decides to StayA COUPLE who say they are victims of a mysterious 10 year haunting say they want rid of what they believe are ghosts occupying their home.Gerald and Julie Jones have li ... 
Investigator gets tormented by a ghost in London (video) Ian Hawke live-streamed his contact with a “ghost” to hundreds of viewers on the social media site.A cup and plate mysteriously fell off a sideboard in Ian’s home be ... 
Exorcist called in to Purge DemonsExorcising demons from possessed souls and removing poltergeists from Welsh homes are two of the more unusual jobs taken on by the Bishop of Monmouth.The Church in Wales ...