Prime Minister Gordon Brown has said that Britain will scrap all its cluster bombs.
Diplomats from more than 100 countries then unanimously passed a treaty to ban the use of the bombs around the world.
Campaigners against the use of the weapons declared the historic announcement in Dublin a triumph.
Simon Conway, co-chair of Cluster Munitions Coalition, said: "It's a combination of years of work and we are extremely happy. We think this will make a huge difference to people around the world and it will save many lives and limbs."
Mr Conway said the Irish Government produced a draft treaty text and the states came together and pushed it through without any changes.
"We got a very strong treaty," said Mr Conway.
"It's very strong on victim assistance, it's very strong on obligations to clear contaminated land and it's a very strong prohibition that we're extremely happy with."
In a statement released by Downing Street, Mr Brown said: "I am delighted that the negotiations in Dublin have come to a successful conclusion, and congratulate the Irish Government and all those involved.
"I am confident that this agreement is in line with British interests and values, and makes the world a safer place."