Officers were called by the ambulance service on Sunday morning at around 8.30am after a man, possibly in his 60s, was found unconscious and partially clothed on Hammond Street, near to Plungington Community Centre.
He had suffered a head injury and was taken to Royal Preston Hospital in a critical condition but died later.
Lancashire Police says the 19-year-old is from Bolton and is currently in police custody.
DI Pete Danby from Preston Police said: “We are still appealing for any witnesses or anyone with information to come forward. If you know anything please get in touch.
“I would like to continue to reassure local residents that we have a team of officers investigating this and we have stepped up our presence in the area.”
A post mortem examination to establish the cause of the man’s death is still to take plave.
Anyone with information is asked to call us on 101 quoting incident reference 768 of January 1st 2017.
Alternatively Crimestoppers can be contacted anonymously on 0800 555111 or online at Crimestoppers-uk.org.