He is set to replace Australia's James Pattinson, who is expected to feature in the Ashes 2019.
This isn't the first stint for Ashwin in County cricket.
Ashwin had earlier impressed in County cricket for Worcestershire
Ashwin previously played for Worcestershire in 2017 and gained valuable experience.
In four matches, the premier spinner picked up 20 wickets that year.
He averaged a commendable 29.18 with the ball, besides taking two five-wicket hauls.
Now the focus for him is a fresh stint with Notts.
Ash will be looking forward to make his presence felt in six matches for them.
Ash looks forward to Notts stint
"It's a good, competitive standard of cricket and I can't wait to get started. I'm really looking forward to joining up with Nottinghamshire, to playing cricket at an iconic venue like Trent Bridge and hopefully contributing to some County Championship victories," said Ashwin.
Several Test specialists from India set to play County
Earlier last month, it was reported that around seven of India's Test specialists may play a few games in order to prepare for the inaugural World Test Championship series in July and August.
Besides Ashwin, the likes of Cheteshwar Pujara, Prithvi Shaw, Hanuma Vihari, Mayank Agarwal, and Ishant Sharma are expected to play County.
With India set to play against the West Indies in the Caribbean post the 2019 World Cup, the BCCI made sure that Test specialists get some vital experience and stay in sync.
The board wanted the players to feature in 3-4 games.
BCCI had held discussions with major County teams
"During the last Test series in England, the BCCI has had discussions with the CEOs of all major counties so that our top Test players can play there in summers," said a BCCI official to PTI last month.
Notable Indians to have featured in County cricket
County cricket is England's first-class domestic cricket competition, which has been played since 18th century.
Over the years, many Indians have played County cricket.
Dating back to as far as Tiger Pataudi in 60s, Farokh Engineer in 70s, the list includes the likes of Sunil Gavaskar, Kapil Dev, Mohammad Azharuddin, Sachin Tendulkar, Sourav Ganguly, Rahul Dravid, Anil Kumble, Ishant Sharma and Cheteshwar Pujara.