Five ministers from Lebanon's two main Shia parties, Hezbollah and Amal, have ended their seven-week boycott of cabinet meetings.
Hezbollah have come under international pressure to disarm
They had objected to a cabinet decision to call for an international tribunal to try those involved in the killing of former Lebanese PM Rafik Hariri.
The boycott has paralysed the Lebanese government since December.
The ministers had demanded that the government declare Hezbollah a resistance movement, and not a militia.
Speaking at a joint press conference with Hezbollah political adviser Hussein al-Khalil, senior Amal official Ali Hasan Khalil said the boycott had now ended.
"The leaderships of Hezbollah and the Amal movement have decided to return their representatives to participate in the government meetings," he said.
The decision came after Lebanese Prime Minister Fuad Siniora told the Lebanese parliament on Thursday that Hezbollah had always been considered a resistance movement.
"We have never called and will never call the resistance by any other name but the resistance and it is a national resistance and we will not use any other expression to describe it but national resistance," he said.
United Nations Security Council resolution 1559, passed in September 2004, considers Hezbollah a militia and calls for it be disarmed.
The Lebanese government says it will deal with armed groups through national dialogue.