The new government has to begin restoring normality
All 30 members attended the session, which also discussed ways of reviving or setting up a functioning administration.
The interim leader, Hamid Karzai, has said his cabinet faces political oblivion unless it can succeed in bringing peace and stability to the country.
He has appealed for billions of dollars in international aid.
Mr Karzai has also said he will investigate reports that United States aircraft killed 60 civilians, including a delegation of elders on their way to the inauguration ceremony in Kabul.
The US says the convoy it attacked was carrying Taleban or al-Qaeda leaders.
In other developments
The BBC's Richard Miron says Mr Karzai's administration has popular backing for the moment at least.
On Sunday, demonstrators paraded through the streets of Kabul, lending their vocal support to the government, and demanding jobs.
One of the organisers, Khalil Delawer, explained why the people had been called onto the streets:
"The first is to welcome the new government; the second is to celebrate the end of fighting; the third is that armed fighters have been called off the streets, and the fourth is to ask Hamid Karzai to give jobs back to professionals."
Mr Karzai and his colleagues described the first meeting as "excellent" and "very friendly".
However, our correspondent says that, in a sign of the complicated task facing the interim administration, some ministers turned up to the first meeting with their own militia men.
He says imposing central control will not be easy after 23 years of warfare and a strong tradition of local independence for tribal leaders.
Convoy controversy
The cabinet met as controversy persists over whether an estimated 60 people killed by US aircraft on Friday included tribal elders, as the locals say, or Taleban leaders as the Americans maintain.
Residents of Asmani Kilai village said the air strikes had killed civilians who had no connection with either the Taleban or al-Qaeda - the terror network led by Osama Bin Laden.
Villager Khodai Noor suggested that a local warlord might deliberately have misinformed US forces - telling them by satellite phone that the convoy was carrying al-Qaeda leaders - to settle a score.
But the US continues to deny it hit Afghan civilians.
The commander of US forces in Afghanistan, General Tommy Franks, said an investigation was under way.
But he defended the pilots' actions, saying: "Friendly forces don't fire surface-to-air missiles at you. We believe it was a bad convoy. We have reason to believe it was a good target."