Its portfolio includes two hotels, Madison's in Belfast and Denvir's in Downpatrick, County Down; and two off-licences.
It runs numerous well-known bars in Belfast, including The Botanic Inn, The Apartment, The King's Head, The Northern Whig, McHugh's, and Horatio Todd's.
The chain of pubs, restaurants and hotels will continue trading, while the administrators, KPMG, seek a buyer for all or parts of the troubled business.
It appears the group has fallen victim to the economic downturn, compounded by high rent levels on properties set during the boom and a high level of company debt.
Botanic Inns grew into Northern Ireland's biggest chain on the strength of its original pub, The Botanic Inn, at 23-27 Malone Road, Belfast, which belonged to the Mooney family.
That such a landmark business is now in administration is a shock that will be felt across the industry, though hope remains it will be saved.
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 is no secret that factors have accumulated over the past year which have made it a very tough trading environment right across the industry.Would JD Wetherspoon plc be interested? Tim Martin is an Old Campbellian.
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."