Sajid Qureshi, an MP for the Muttahida Quami Movement, killed on his way home after Friday prayers in North Nazimabad.
A politician from Pakistan's liberal Muttahida Quami Movement (MQM) party, his son, and a passer-by outside a mosque have been killed in Karachi after unknown assailants opened fire at close range.
Sajid Qureishi, a recently elected member of parliament, and his 25-year-old son were targeted in a drive-by shooting on their way home after Friday prayers in the North Nazimabad area of the city.
His bodyguard has also been wounded.
"Gunmen on a motorcycle fired at (Sindh) provincial assembly member Sajid Qureshi, his son and a pedestrian when they were coming out of mosque," senior police official Amir Farooqi told the AFP news agency.
Qureshi was a member of the secular Muttahida Qaumi Movement (MQM), the most powerful political party in Karachi now considering whether to join the government in southern Sindh province.
"He died on the spot, while his son and the third victim died at hospital," Farooqi said.
Nasir Jamal, a senior member of MQM, confirmed the death of Qureshi and his son.
MQM has long held sway in Karachi, a port city on the Arabian Sea, and its leader-in-exile Altaf Hussain lives in London.