The two companies have 16 outlets in their portfolio, including two hotels, Madison's in Belfast and Denvir's in Downpatrick and two Dr:nk off sales.
They run well-known bars in Belfast including The Botanic Inn, The Apartment, The King's Head, The Northern Whig and McHugh's.
Over 500 people are employed across the venues.
The administrators, John Hansen and Stuart Irwin of KPMG in Belfast, said their intention is for the venues to continue to trade as normal and it is "business as usual".
"The Joint Administrators are currently undertaking a review of the business and have spoken to management, the workforce and other key stakeholders in an effort to determine a successful outcome to the administrations, namely the survival of the business as a going concern," a statement said.
The Joint Administrators said they will be keeping management and employees informed of the progress of the administrations in the coming days.
They said they would not make any further comment until they have completed their review.
Colin Neill, chief executive of Pubs of Ulster said it was disappointing news.
"Botanic Inns is an iconic brand for the city of Belfast and right across Northern Ireland. It has always had the highest reputation and regarded as one of our Blue Chip companies and we must do all we can to help support it at this time," he said.
"We welcome the Administrators intention that the venues will continue to trade as normal and that regulars and visitors to the Botanic Inns pubs and bars should be reassured that they are opened for business.
"It is no secret that factors have accumulated over the past year which has made it a very tough trading environment right across the industry. The revenue reserves normally built up by publicans during the Christmas season have suffered in the current trading environment and the negative impact of the recent flag protests compounding the problems faced by the trade."
Mr Neill added that the number of pub licenses in Northern Ireland has decreased by over 200 since 2007, which he put down to several factors including the impact of supermarket pricing of alcohol.
"It is important to reiterate that the pub industry is a key economic driver and its health and vitality are crucial in the sustainability of the economy as a whole. It must be protected."