Edinburgh wing Darcy Graham and Gloucester centre Chris Harris start in place of Tommy Seymour and Duncan Taylor, the latter moving to the bench.
Half-backs Greig Laidlaw and Finn Russell start together for the 35th time, equalling the national team record of legendary pairing Roy Laidlaw [Greig’s uncle] and John Rutherford.
It's all change in the back row, with no place for John Barclay in the 23. Jamie Ritchie starts in place of the injured Hamish Watson at openside, with Watson’s replacement Magnus Bradbury on the blindside and Scarlets Blade Thomson at number 8.
Stand-off Adam Hastings, scrum-half George Horne and tighthead Zander Fagerson all come on to the bench after not being involved in last Sunday's 27-3 thumping by Ireland in Yokohama.
Townsend said: “Samoa are a team capable of scoring points from anywhere on the field. They play an ambitious brand of rugby and their team is full of skilful and powerful players.
“We had worked hard in our build-up this tournament to deliver our best rugby but we were well below this level in our opening game against Ireland. We’ll need to be much better on Monday night against such a dangerous opponent.”
He added: “It’s been a long week building towards a game where we intend to put a lot of things right.
“The players have responded well in training, know what is required of them and are hungry to deliver the kind of performance that keeps us in the world cup.
“The reality is we now have to win our next three games to make it out of our pool, so the knockout stages for us begin this Monday night. I firmly believe this group are ready to take on that challenge.”