The statement comes amid widespread speculation that Chouhan, who is in his third term as CM, would be given a cabinet position at the Centre.
Chouhan had earlier dismissed the rumors saying he'd continue leading the state government.
No Union cabinet position for MP CM Shivraj
Shah: BJP to win 200 seats in 2018 MP elections
Shah said the BJP expects to win "no less than 200 seats" out of 230 in the 2018 MP state assembly elections and all 29 Lok Sabha constituencies in the 2019 polls.
Shah reiterates pledge not to become cabinet minister
"My term as a legislator in Gujarat is nearing completion, so I opted for the Rajya Sabha," Shah said. "Now, I will continue working for the party. I will remain in the organization and will never join the Union cabinet. I am announcing this officially."