The title has been acquired from a consortium of individual investors led by Sir Bernard Gray.
The weekly magazine has a circulation of around 120,000 with around 75% of its revenue derived from subscriptions.
In 2021, the business is expected to generate cash operating income and operating profit of roughly £7mln on revenues of more than £20mln.
“New Scientist is a world-renowned publication loved by its readers, and we are both thrilled and proud to welcome it to the DMGT family,” said Lord Rothermere, the chairman of Daily Mail and General Trust (DMGT).
“They are a specialised and talented team who showcase the best of science journalism, bringing integrity, curiosity and craftsmanship to their work,” he added.
Paul Zwillenberg, the chief executive of DMGT, said the group is “committed to supporting the talented team and their plans for the future”.
The Press Gazette said “science and subscriptions are two strong areas for publishers to be in right now, so DMGT’s purchase of New Scientist makes perfect sense”.
“The £70mln purchase price is ten times this year’s expected operating profit for the title. The weekly targets a specialist audience so looks in some ways an unlikely stablemate for i, Metro and the Mail titles but it will benefit from being part of a heavyweight publishing machine with huge expertise and resources when it comes to growing print and online businesses,” the trade paper added.
Shares in DMGT were up 2.6% at 934p in mid-morning trading.