The rally comes as the Brotherhood`s Freedom and Justice Party is set to elect a new party chief Friday after President Mohammed Morsi resigned the leadership after his June election.
Egyptian protesters from the revolutionary and leftist political groups demanded the dissolution of the Constituent Assembly for not representing all Egyptian communities.
The protesters marched from a mosque near the epicenter of the Egyptian uprising in Tahrir Square to the nearby Syrian Embassy.
Hundreds of Egyptian activists are demanding a clear road map to democracy and an end to military trials for civilians.
Hosni Mubarak has told interrogators he did not order security forces to open fire on protesters.
Day in Pics: 28th January
Showbiz World - January 28, 2015
President Barack Obama's speech at Siri Fort auditorium