Iain Henderson and Louis Ludik got the tries
Ulster have continued their unbeaten start to the Guinness Pro 12 season.
The province came out on top against Scarlets by a 19-8 scoreline at Kingspan Stadium.
With Paddy Jackson's penalties putting Ulster in control early on, a try from Louis Ludik after being set up by Ireland centre Stuart McCloskey made it 11-0.
Scarlets got their only try with four minutes to go when Will Boyde scored.
But Iain Henderson's 80th minute try made sure of the victory for Ulster.
They have now made it three wins from three.