Curtis Hulme, 27, left HMP Kirkham on Monday, August 27 and failed to return.
He is described as white, 5ft 9in to 5ft 11in tall, of slim build with short brown hair and brown eyes.
He has a scar on the middle knuckle of his left hand, a three inch scar on his left wrist and another scar on the little finger of his right hand.
Hulme was sentenced to five years in prison for robbery in September 2016.
He has links to the Rochdale area of Greater Manchester.
Police are appealing for information about his whereabouts with people urged not to approach him.
A Lancashire Police spokesman said: “Hulme is wanted by police after absconding from prison.
“He is a potentially violent offender and we would urge anyone who has seen him not to approach him, but instead contact us immediately.”
Anyone with information can contact police on 101 or email [email protected] quoting log reference 1545 of August 27.
Alternatively, independent charity Crimestoppers can be contacted anonymously on 0800 555111 or online at crimestoppers-uk.org