The Competition and Consumer Protection Commission has cleared the proposed merger of betting firms Paddy Power and Betfair.
The Commission said the deal will not substantially lessen competition in the betting industry in Ireland.
Last month Paddy Power shareholders approved the merger with Betfair at the company's EGM in Dublin.
Earlier in 2015, the two companies said their boards had reached agreement on the terms of a recommended £6bn all-share merger.
The merged entity will be called Paddy Power Betfair and will be one of the world's largest public online betting and gaming companies.
The merger will result in Paddy Power shareholders owning 52% of Paddy Power Betfair and Betfair Shareholders owning 48% of Paddy Power Betfair on a fully diluted basis.
Paddy Power shareholders will receive a special dividend of €80m just before the deal closes.
Paddy Power Betfair will be headquartered in Dublin and is expected to maintain a significant presence in both Ireland and the UK.
When the deal is complete, Breon Corcoran, who is currently CEO of Betfair, will become CEO and an executive director of Paddy Power Betfair.
Paddy Power's current CEO Andy McCue will be become the company's COO and an executive director of the merged firm.
The deal will bring together Paddy Power's 336 shops in the UK and 252 stores in Ireland with Betfair's online betting exchange.
Around 80% of their combined annual revenues will be from online business, making it a force to be reckoned with in the gambling sector as it increasingly moves online.
The newly merged group will have customers from more than 100 countries, with aims for further international expansion across continental Europe, the US and Australia.
Paddy Power was founded in 1988 by the merger of three existing Irish bookmakers and it has become well known for its irreverent marketing style.
Its rapid growth in recent years has seen it build more than 300 betting shops in Ireland and the UK, and it now ranks as the third largest online bookmaker and sixth largest online gaming business in Britain and Ireland.
Betfair comes from a newer side of the bookmaking fence. In 1999, professional gambler Andrew Black and city professional Edward Wray joined forces to form The Sporting Exchange, which went on to launch the Betfair Betting Exchange the following year, offering the market something of a revolution.
Its first market was the Epsom Oaks in 2000, but the new approach to gambling quickly took off by giving punters the chance to take bets and subsequently bet in play. Betfair floated on the London stock exchange in 2010.