Details of the kidnapping, including clues as to who might be behind it, were not immediately available.
Al-Hassani is a Sunni who has served as speaker of the National Assembly through difficult negotiations to hammer out the draft constitution that was approved in a national referendum in mid-October.
Meanwhile, in Baghdad, police said two car bombs exploded tonight near a Shi'ite mosque. No casualty figures were available.
A suicide car bomb earlier in the day killed at least five police officers in Baquba, northeast of the capital.
Georgia's Defense Ministry also said four Georgian troops were wounded, including one seriously, by a land mine in the same city.
In western Iraq, the U.S. military said today that a suspected high-ranking insurgent leader, Majid Adnon Swedowi, was captured on 5 November in a raid near Ramadi.
The military also said it believes that most insurgents have been cleared out of the town of Husayba, near the Syrian border, in a major operation against militants in the area.
(compiled from agency reports)
Also today on Iraq:
Assassination Of Another Lawyer In Hussein Case Throws Trial Into Question