The man at the centre of a large scale search along the River Foyle was located close to Altnagelvin Hospital in the early hours of Wednesday morning.
At around 7.30pm on Tuesday, police were made aware of concerns about a man close to the river.
Police officers began a search of the river embankments and a police helicopter was also deployed.
Foyle Search and Rescue dispatched two boats, three mobile units and land crews to help with the search for the missing man.
At around 2.30am police located the man close to Altnagelvin Hospital and he was taken to Accident and Emergency for treatment.