The European Commission on Monday approved Mars's acquisition of Kellanova, saying an antitrust probe found it would not raise competition concerns.
The European Commission, the EU's antitrust regulator, had launched an investigation in June over concerns that the transaction would lead to higher prices for consumers.
But this concluded that Mars, the maker of M&M's and Snickers, would not benefit from much stronger bargaining power with retailers as a consequence of the purchase.
"We looked very carefully at this deal to make sure that Mars would not gain extra power over retailers, power that could lead to for example higher prices for shops and, ultimately, for consumers," European Union competition chief Teresa Ribera said.
"Our review found no evidence that this risk exists, so we have decided to approve the acquisition."
The commission argued this was due to the fact that Kellanova's products, which include Pringles and Pop-Tarts, have a long shelf life and are usually "the object of impulsive and infrequent purchases".
And snack-buyers were unlikely to start shopping at a different store if the two firms' products were to become unavailable at their local supermarket.
The deal was approved unconditionally.
Mars announced in August last year that it would acquire snack food business Kellanova, marking a multibillion dollar agreement set to result in a new industry giant.
The deal valued Kellanova at $35.9 billion (£27.95bn). It owns legacy Kellogg brands, including in snacks, crackers, and frozen breakfasts, after spinning off its North American cereals business in 2023 as WK Kellogg Co.
The US Federal Trade Commission (FTC) has in June cleared the deal after nearly a year of investigation, noting that the transaction does not meet the standard for an anticompetitive merger.