Mir, 47, sustained bullet injuries after he was shot at near Natha Khan bridge soon after he left the Karachi airport for his office, initial reports here said.
GeoTV reported that Mir, who has security guards with him, called up office to inform them of the attack on him. He was rushed to a hospital in a private car.
Four gunmen riding two motorcycles opened fire on Mirs car about six kilometers from the airport, GeoTV said.
Dawn reported the gunmen opened fire at the vehicle at 5:30 pm and Mir was admitted to hospital in a state of unconsciousness.
Geo News Islamabad bureau chief Rana Jawad said Mir told him after being attacked that the gunmen were following him and continued to fire at the car.
A popular news anchor, terrorism expert, and security analyst, Mir currently hosts political talk show Capital Talk on Geo TV.
In November 2012, a bomb was recovered from under his car which was believed to have been planted by the Pakistani Taliban.
Just last month, senior analyst Raza Rumi was shot at in Lahore that killed his driver.
The issue of security of media personnel was raised by Committee to Protect Journalists, a media advocacy group, during a meeting with Prime Minister Nawaz Sharif last month.
The Prime Minister had promised to take appropriate steps to ensure security of journalists in Pakistan.