Mark Stoner-Seed (52) was released on a temporary licence in the Bristol area on Friday 23rd January, but failed to return at the designated time to HMP Leyhill.
Stoner-Seed is serving a life sentence for murder, grievous bodily harm with intent and arson with intent.
He is described as white, bald, around 5ft 7ins, of large build, with blue eyes.
Stoner-Seed should not be approached.
Anyone with information on his whereabouts should call Avon and Somerset Police on 01275 818340 quoting crime reference G8061/15 or Crimestoppers anonymously on 0800 555111.