European Commission President Jose Manuel Barroso said the money would help the West African state become “stable, democratic and prosperous”.
The conference is the first since France sent troops to oust Islamist rebels from northern Mali in January.
Mali’s government has a 4.3bn-euro plan for “a total relaunch of the country”.
It includes rebuilding government institutions and the military, repairing damaged infrastructure, organising presidential elections, holding dialogue with rebel groups in the north, and stimulating the economy.
‘Good start’
After meeting the European Commission chief in Brussels on Tuesday, Mali’s interim President Dioncounda Traore said he hoped about 2bn euros would be raised at the donors’ conference.
Analysis
Mali had its unfortunate place in the limelight with the Islamist occupation of the north and the equally dramatic French military action.
Now it is just another broken state among many. And in places the West sees as marginal donors usually want quick – and preferably cheap – results.
For example France has pressed Mali to hold national elections before the end of July. But many Malians see this as completely unrealistic in a country where basic institutions, like the army and schools, need rebuilding.
The aid agency Oxfam said donors would have to commit to development funding in Mali for at least 15 years for results to be sustainable. “Crises such as Afghanistan and Somalia,” Oxfam said, “have shown that a narrow approach to winning a military conflict is never enough to achieve long-term peace and security.”
“I think that’s a good start,” he told a news conference. “Tomorrow or the day after tomorrow, in a week or in a month, it is clear that the international community, the European Union, will inject a lot more than that.”
Mr Barroso said the aid would benefit Europe as well as Africa.
“The support of the international community is essential to establish a Mali that is stable, democratic and prosperous,” he added. “But the principal actors in this transition are the Malians themselves and their government.”
He said the EU welcomed the Transition Roadmap, aimed at establishing a full return to democracy and stability in the country, and the Plan for the Sustainable Recovery of Mali, which Malian officials will present at the conference on Wednesday.
Officials say 103 international delegations, including 10 heads of state and government, will attend the meeting, which was organised by Mr Barroso, Mr Traore and French President Francois Hollande.
Since the French-led military intervention at the start of the year, the Islamist rebels have been pushed back from the main urban centres of northern Mali. However, some fighters have retreated to hideouts in the mountains and desert, from where they launch isolated attacks.
Tens of thousands of refugees also remain in neighbouring Burkina Faso, Mauritania and Niger.
France nevertheless began withdrawing the first of its 4,500 troops in the country last month. It hopes to have only 1,000 remaining by the end of the year.
They are due to work alongside peacekeepers from the United Nations’ Multidimensional Integrated Stabilisation Mission in Mali (Minusma).
Mr Traore also told Tuesday’s news conference that Mali’s presidential elections would take place on 28 July, after months of speculation about the date. He said neither he nor any member of the transitional government would stand in the poll.
BBC international development correspondent Mark Doyle says the Islamists were only able to occupy large parts of Mali in the first place because of because of a weak and corrupt central government.
Rebuilding state institutions is therefore a priority, but it is also an enormous task, our correspondent says.