The month on the Islamic calendar will begin on Saturday as the moon was sighted on Friday evening, stated Ruet-e-Hilal Committee.
Mufti Muneebur Rehman made the announcement after a meeting of the Ruet-e-Hilal Committee.
The government has set Aug 12-15 as the official Eid holidays.
Eid-ul-Azha is celebrated on the 10th of the month of Zil Hajj.
The Muslims sacrifice animals during the festival representing shunning off the evil inside and seeking the blessing of the almighty.
Suadi Arabia and other Middle Eastern countries will celebrate Eid-ul-Azha on Aug 11, as the moon was sighted there on Thursday. The Hajj will be performed on the day before.
