The kidnapping of Ahmed Awad bin Mubarak comes as Yemen remains gripped by Shiite Houthi rebels and battered by regular al-Qaida attacks.
Officials said gunmen kidnapped bin Mubarak and his two guards when they stopped their car in central Sanaa. They said there was no ransom demand made.
One of the youngest politicians in Yemen, 46-year-old businessman-turned-political figure bin Mubarak emerged during the uprising that forced longtime leader Ali Abdullah Saleh to step down in a US-backed agreement.
Critics say the Houthis are a proxy for Shiite Iran, charges the rebels deny.
Bin Mubarak is personally at odds with the Houthis. He was the president's choice for prime minister last October, but his nomination was derailed after Houthis opposed him for his ties to the president.
Meanwhile Saturday, thousands demonstrated in central Sanaa against the Shiite rebels in a protest called by civil society groups.