The previous Islamist-dominated legislature was dissolved by a court ruling in 2012.
The following year, the then General Sisi ousted President Mohammed Morsi following massive protests against him and his Muslim Brotherhood party.
Egypt's new parliament has just 15 days to ratify over 300 new laws issued.
Newly elected MPs were sworn in on the first day. They were then due to elect a speaker and two deputies.
Parliament comprises 568 elected members and is dominated by an alliance loyal to President Sisi.
Sunday's session was supposed to be mostly procedural but it was disrupted by one outspoken member.
Murtada Mansour, a President Sisi supporter, at first refused to read the official text of the MPs' oath, before relenting and "hurriedly and casually" reciting it, the Associated Press reported.
Mr Mansour was angry at parts of the text endorsing the ousting of former President Hosni Mubarak in 2011, which some pro-government figures now see as a mistake, according to the agency.
Egypt's parliament has opened for the first time in more than three years, packed with supporters of President Abdel Fattah al-Sisi.