Attackers shot a security guard and seized the envoy in Baghdad on Tuesday, police said.
Police Lieutenant Thair Mohammed said Naji al-Noaimi was abducted in the city's al-Mansour district at about 10pm (1800 GMT) as he was walking from the embassy to his home nearby.
He added that a Sudanese security guard, Bedawi Ahmed Ibrahim, was shot by the attackers.
The foreign ministry in Abu Dhabi confirmed that one of its diplomats in Baghdad had disappeared, the Emirates state news agency reported.
In July 2005, al-Qaeda in Iraq kidnapped and killed two Algerian and one Egyptian diplomat, Ihab al-Sherif, in an apparent campaign to prevent Arab and Islamic countries from strengthening ties with the Iraqi government.
Arab nations have since then been hesitant to send ambassadors to Baghdad.
Senior envoys from Pakistan and Bahrain have managed to escaped kidnap attempts. More than 40 diplomatic missions are currently in Iraq.
Two Moroccan embassy workers, Abderrahim Boualam and employee Abdelkrim el Mouhafidi, disappeared in October 2005 while driving from Jordan.