Hook scored 23 points in a perfect kicking performance
Ospreys: (22) 50
Tries: R Jones, Walker, Byrne, Bateman, Lloyd
Cons: Hook (4), Connor
Pens: Hook (5)
Scarlets: (10) 24
Tries: Pen, Peel, Gavin Evans
Cons: C Thomas (3)
Pen: C Thomas
The Ospreys bounced back from their Blues loss for a crushing west Wales derby win before 20,500 in Swansea.
Ryan Jones led the way with the opening try, Nikki Walker also crossing before the break after a Scarlets penalty try that saw Justin Marshall sin-binned.
Dwayne Peel and Lee Byrne traded tries after the break but the Ospreys greater power and resources began to tell.
Replacements Lyndon Bateman and Andy Lloyd secured the bonus, while the impressive James Hook kicked 23 points.
The Scarlets - who had seen Stephen Jones drop out during the warm-up after suffering a back spasm - lost a host of players to injury and will be concerned ahead of the New Year's Day clash at Cardiff Blues.
You have to be happy with scoring that number of points and getting that sort of result
The game was the second-ever sell-out at the Liberty Stadium and a record attendance for a Welsh region in the Celtic/Magners League.
Marshall fuelled a strong start by the home side, and his grubber kick set up the first try.
Byrne gathered the bouncing ball, Marshall shipped it on to man-of-the-match Jones, and the big number eight handed off Peel and carried two other Scarlets defenders across the line.
Hook converted and added a second penalty, but the visitors hit back through a Ceiron Thomas grubber kick.
Marshall was under pressure as he got to the ball behind the try line and he chose to deliberately knock the ball out of play, giving referee Nigel Owens little option but to yellow card him and award the penalty try.
Thomas converted, but the impressive Hook - playing at outside-half rather than centre - took the Ospreys' lead out to 22-7 with three more penalties, Thomas getting one back just before half-time.
A dazzling Shane Williams counter attack got the Ospreys on the front foot after the break, before Hook seemed to be denied a legitimate try.
He kicked ahead from a quickly taken penalty and looked to have grounded the ball as Mark Jones slipped, but with no video referee to turn to no score was awarded.
Peel sniped superbly from the base of a ruck for a try to give the Scarlets hope, but Byrne immediately hit back by scything through the Llanelli side's midfield defence to score under the posts.
The home team showed the power in their squad by wheeling on their powerful replacements bench, and Bateman peeled off a short-range line-out for the bonus-point try.
Hook converted to complete a 100% kicking performance, before Lloyd rolled over from short range, Shaun Connor converting.
Some consolation came for the visitors as Peel and Dafydd James sparked a counter-attack that saw Gavin Evans cross in the corner for the final try.
Ospreys coach Lyn Jones:
"We'd had an awful start against the Blues last week, but this time the Scarlets looked like they hadn't played for a while.
"But we were too strong for them and deserved to win.
"Every time you face the Scarlets in a local derby like this there's a lot of spirit in the game and you have to be happy with scoring that number of points and getting that sort of result.
"But I'm sure it'll be different when we go to Stradey Park later in the season."
Ospreys: Byrne, Walker, Parker, Henson, S. Williams, Hook, Marshall, D. Jones, B. Williams, A. Jones, Cockbain, A. Jones, Tiatia, Tandy, R. Jones.
Replacements: A. Bishop for Henson (68), Spice for Marshall (68), Griffiths for D. Jones (65), Shervington for B. Williams (78), Bateman for Cockbain (65), Lloyd for Tiatia (65), Connor for Hook.
Llanelli Scarlets: B. Davies, James, King, G. Evans, M. Jones, C. Thomas, Peel, I. Thomas, Rees, Dunlea, Afeaki, MacLeod, D. Jones, G. Thomas, Popham.
Replacements: Watkins for B. Davies (49), Owen for Rees (80), Manu for Dunlea (56), Bater for Afeaki (40), Cooper for MacLeod (21). Not Used: Stuart-Smith, S. Jones.
Referee: Nigel Owens (WRU)