The first blast, in a church north of Cairo in the Egyptian Nile Delta city of Tanta, kills at least 27 people, while another 11 die in a suicide attack at a church in Alexandria.
Two separate bombings in churches in Egypt killed at least 38 people and injured dozens others on Sunday, officials said.
A suicide bomber killed at least 11 people and injured 21 in front of a church in Alexandria, Egyptian state television and the health ministry said.
The blast occurred hours after a bombing rocked a Coptic church in Tanta in Egypt's Nile Delta, killing at least 27 people and injuring 60.
Daesh claimed responsibility for both attacks.
The first blast took place during a Palm Sunday mass at the Mar Girgis Coptic Church in the city of Tanta, about 120 kilometres from Cairo, an Interior Ministry official said.
Local media showed footage from inside the church in Tanta, where a large number of people gathered around what appeared to be lifeless, bloody bodies covered with paper.
TRT World spoke with Cairo-based journalist Sean David Hobbs for the latest.
Pope condemns blast
Pope has condemned the blast and appealed to terrorists, arms manufacturers and traffickers to stop.
Grand Sheikh Ahmed el-Tayeb, head of Egypt's Al-Azhar has condemned the attack, calling it a "despicable terrorist bombing that targeted the lives of innocents."
Christians make up around 10 percent of Egypt's population and have repeatedly been targeted by militant groups.
Tanta was also the site of another attack earlier this month when a policeman was killed and 15 were injured after a bomb exploded near a police training centre.
A suicide bombing claimed by Daesh at Cairo's largest Coptic cathedral killed at least 25 people and wounded 49 in December.