"Given the current circumstances and our solidarity with the families of the dead, we are going to limit our celebrations to Easter mass," a statement said.
The traditional handing out of sweets to children by Coptic Pope Tawadros II before the start of Easter mass on Sunday will also be cancelled.
"There will be no decorations in churches and the rooms normally reserved for the reception of worshippers wishing to exchange season's greetings will remain closed," an official at the Coptic patriarchate told AFP.
Palm Sunday church bombings claimed by IS kill at least 43 in Egypt
The Islamic State jihadist group said it was behind the bombings at churches in the cities of Tanta and Alexandria, and threatened further attacks against Egypt's Christian minority.
The government has ordered a three-month state of emergency which was unanimously approved by parliament on Tuesday.
Sunday's first bombing at the Mar Girgis church in Tanta, north of Cairo, killed 28 people. The second struck outside Saint Mark's church in Alexandria, killing 17 people after a suicide bomber was prevented from entering the building.
Pope Tawadros II had led a Palm Sunday service in the church shortly before.
The violence comes ahead of Catholic Pope Francis's first visit to Egypt, which a Vatican official said will go ahead as planned on April 28 and 29 despite the attacks.
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