Qanuni was chosen to lead the 249-seat lower house of parliament with 122 votes against 117 for his closest challenger, Abdul Rabb Rasoul Sayyaf.
Qanuni is an ethnic Tajik who came in a distant second to Karzai in the 2004 presidential elections.
Yesterday, a close ally of Karzai -- Sibghatullah Mojadidi - was picked to head the 102-seat upper house.
The Afghan parliament met on 19 December for the first time in more than 30 years, capping a transition to democracy that began with the U.S.-led
toppling of the Taliban regime in 2001.
(RFE/RL's Afghan Service/Reuters)