Sisi, who won election in a landslide in 2014 after leading the army in ousting Muslim Brotherhood's Mohamed Mursi a year earlier, submitted documents to become the first candidate to register for the March 26-28 vote.
Any other candidates have only until Jan. 29 to register before a final list is announced on Feb. 20, according to election rules.
Sisi's popularity has been damaged by austerity reforms, security problems and a crackdown on dissidents and political opponents, his critics say.