The ruling National Democratic Party (NDP) said on Thursday it had officially set the date during a meeting of the party's general secretariat chaired by NDP secretary-general Safwat al-Sherif.
"25 May, the day on which the referendum on the amendment to Article 76 of the constitution will be held ... shall be a day of national pride, as every Egyptian going to the polls will be proud to have participated with his vote in the making of a new dawn," an official statement said.
The revision of Article 76 was endorsed on Tuesday by an overwhelming majority of the 454-seat lower house dominated by President Hosni Mubarak's NDP, despite an opposition walkout.
The opposition reaction
The opposition, both secular and Islamist, charges that the amendment sets such tight conditions for registration that only the ruling party will be able to field a candidate, undermining the whole point of the reform.
Al-Wafd party, the largest legal opposition political party in the country, said it would boycott the vote on the changes and urged Egyptians to stay at home on referendum day.
The banned but tolerated Muslim Brotherhood, arguably Egypt's strongest unofficial opposition group, called on supporters to come out in force, but to vote against the amendment.