Tributes have been pouring in for Tony Gregory.
The Taoiseach has said he served his community with great dedication and distinction.
Brian Cowen said Tony Gregory was a proud Dubliner, a great advocate for his community and a diligent public representative.
"He had an insightful knowledge of many issues especially social deprivation and the problems caused by drugs. I have no doubt he will be greatly missed by all his Oireachtas colleagues who respected him greatly,"
Mr Cowen added.
Health Minister Mary Harney said the Dublin Central TD was a tireless fighter against the scourge of drug abuse.
Fine Gael leader Enda Kenny has also paid tribute to Mr Gregory.
"Tony Gregory was a fearless defender of his inner city constituents, proud of his heritage, and absolutely courageous in standing up to drug barons and drug pushers. He epitomised his love of country by his continuous and frequent use of the Irish language, which he spoke so well and with such clarity," Mr Kenny said.
Labour Party TD Joe Costello shared the Dublin North constituency with Tony Gregory.
He said Tony Gregory dedicated his career to improving the living conditions for the people of his area.
He added he was "shocked and saddened" to hear of Mr Gregory's death, describing the independent TD as "a legend in his time".
"He was deeply committed to the eradication of poverty in the north inner city and much of his political life was spent on seeking to improve the quality of housing and education and on combating unemployment, particularly in the north inner city," Mr Costello said.