Google won unconditional approval from the European Commission today to buy rival web advertiser DoubleClick for $3.1 billion.
The approval after an investigation by European competition officials follows clearance from US antitrust authorities received late last year.
The European Commission, the European Union's executive arm, said the companies operate in different parts of the online advertising world and that their deal was no marriage of competitors.
"Google and DoubleClick were not exerting major competitive constraints on each other's activities and could, therefore, not be considered as competitors at the moment," it said.
Google has by far the strongest position in web searching in Europe. That gives it an edge on the simple ads it sells which appear on its search pages.