Qadri, who shot Taseer 28 times in 2011 in broad daylight in an upmarket locality of Islamabad for criticising the blasphemy laws, was hanged in Adialia jail of Rawalpindi city at around 4:30 am, officials said.
Within hours of the hanging, street protests broke out in several cities by the supporters of Qadri, who considered him as a hero for defending the faith, and had threatened violence if he was executed.
Activists of Sunni groups, who had given a hero-like status to Qadri, blocked main intersections in Rawalpindi, cutting off the main link with capital Islamabad.
Police and paramilitary security personnel were patrolling the roads.
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A senior police official said that high-alert had been issued in Rawalpindi and rest of Punjab province to tackle any untoward situation.
"Security forces were on high alert and extra police were being deployed to clear the roads," a police officials said.
After assassinating Taseer in January 2011, Qadri admitted the killing and said he objected to the governor's calls to reform the blasphemy laws.
An Anti-Terrorism Court had convicted and condemned Qadri to death in the same year, a ruling also upheld by the Islamabad High Court and the Supreme Court.
A review petition of Qadri was also turned down by the top court on December 14 last year, leaving him with the last option of to file a clemency appeal to President Mamnoon Hussain.
His mercy appeal was also rejected by the President.
Sunni Tehreek chief Sarwat Ijaz Qadri condemned the hanging.
"It is black day in the history of the country. Those who executed Qadri have only spoiled their chances of success hereafter," he said.
The funeral prayer of Qadri will be held tomorrow in Rawalpindi.
Blasphemy is a sensitive issue in Pakistan, with even unproven allegations often triggering mob violence.
The controversial law was introduced by former military dictator Zia-ul Haq in 1980s and so far hundreds of people have been charged under them.