The accord was signed Monday by the Afghan trade and industry minister, Anwar Ul-Haq Ahady, and Iran's deputy oil minister, Alireza Zeyghami.
Two-thirds of the export deal was for fuel oil, a category that includes diesel and fuel for agricultural, industrial and heating uses, according to Zeyghami. A quarter was for petrol and around 10pc was jet fuel, he said.
The agreement was announced as Iran is subject to Western sanctions against its oil and gas sectors over Tehran's controversial nuclear programme. The United States and Europe are poised to increase sanctions in coming weeks.
Iran's oil ministry in February said it hoped Afghanistan would buy "all its needed (fuel) products from Iran."
But the Afghan government responded by saying it could not afford to do so and would continue to also buy from central Asia and Pakistan.
About one third of Afghanistan's fuel needs, imported from Russia, Turkmenistan and Iraq, transit through Iran.