The powerful suicide truck bombing struck a guest house, killing at least 30 people and wounding as many as 90, the Interior Ministry said.
No group immediately claimed responsibility for the bombing in Pul-e-Alam, the capital of Logar province.
The attack came as U.S. and NATO troops are prepared for the start of the final withdrawal from Afghanistan.
The attack came on the eve of the official date set for the start of the final withdrawal of U.S. and NATO troops from Afghanistan.
Afghanistan has seen a surge in violence as peace talks that started in September between the Taliban and the Afghan government have so far failed to achieve a breakthrough.
The majority of bomb attacks in Kabul in recent months have been sticky bombs, which are explosive devices with magnets attached to vehicles and detonated by remote control or timer.
Since 2001 when the United States invaded Afghanistan, over 100,000 people have been killed in the war, including more than 4,000 ISAF soldiers and civilian contractors, more than 62,000 Afghan national security forces, 31,000 civilians, and even more Taliban members.