According to Director Health Karachi, target of immunizing 685,000 children has been fixed for the campaign.
The drive will continue till 05:00 pm without any interval.
Strict security arrangements have been made for the three-day anti-polio drive.
Pakistan is amongst the only three countries of the world where polio cases are reported. The country was slapped with travel restriction by the World Health Organization (WHO).
The attacks on polio teams and the refusal of parents to immunize their children are one of the contributing factors to the increase in polio cases each year.