Hosted by Germany for the third time, the conference on Wednesday is designed to assess the pace of progress in reconstructing the war-ravaged nation and commit the international community to further pledges on military, financial and political support.
After an opening speech by German Chancellor Gerhard Schroeder, the first part of the first day's business will focus on Afghanistan's political future - essentially, how to stabilise the central government under President Hamid Karzai.
A second session will look at the pace of economic reconstruction and aid, and how much more needs to be done.
The second and closing day of the conference on Thursday will tackle security problems plaguing Afghanistan, notably pacifying the lawless provinces where the Kabul government's authority is almost non-existent.
The talks, under the title Afghanistan and the International Community: A Partnership for the Future, are behind closed doors at the InterContinental Hotel in west Berlin.
Karzai and Afghan Foreign Minister Abd Allah Abd Allah are leading the Kabul delegation. Pakistan is sending Foreign Minister Khurshid Mahmud Kasuri, and China his counterpart Li Zhaoxing.
US Secretary of State Colin Powell is one of the highest-profile delegates, while other foreign ministers to attend include Alexander Downer of Australia, Jack Straw of Britain, Brian Cowen of Ireland - which holds the rotating EU presidency - Hwang Doo-Yun of South Korea and Sergei Lavrov of Russia.
Japan, which is co-hosting the conference with Afghanistan, Germany and the United Nations, has sent the former UN refugees agency chief Sadako Ogata.
Other nations represented range from Kyrgyzstan, Tajikistan and Uzbekistan in central Asia to Luxembourg, in the heart of Europe.
NATO chief Jaap de Hoop Scheffer and Jean Arnault, the United Nations envoy to Afghanistan, are also due to attend.