The Saints have dismissed the 47-year-old and replaced him with the Argentine, who will take charge for Monday's Premier League clash against Everton at St Mary's.
The Saints are currently 15th in the table following a good run of form that has seen them lose just twice in their last 12 games, but that has not been enough to keep Adkins, who had been on the hot seat for some time, at St Mary's.
“This decision has been made with the long-term ambitions of Southampton Football Club in mind. Whilst we acknowledge the contribution Nigel has made during the past two years, for the club to progress and achieve our long-term targets a change was needed," Southampton executive chairman Nicola Cortese said.
“Mauricio is a well-respected coach of substantial quality who has gained a reputation as an astute tactician and excellent man manager. I have every confidence that he will inspire our talented squad of players to perform at the highest possible level.
“He also shares my belief that the most successful clubs are built by nurturing young players through a development system that provides a clear path to the First Team, thereby creating a culture that keeps them at the Club for the long term. This is an approach he has employed with great success in the past and I look forward to him bringing that experience and expertise to Southampton.”
Pochettino, a former Argentina international who has previously managed Espanyol, is excited for the opportunity to lead the Saints to safety and a place in the top flight next season.
"This is the kind of opportunity that any coach would relish. Southampton is a club with great heritage, and an even more exciting future," Pochettino said. "There is a clear vision to take the club to a new era of sustained success in the Premier League, and beyond, which I’m delighted to be part of.”