Egyptians will choose between between the Muslim Brotherhood and a candidate from the Mubarak-era regime when the presidential election goes to a run-off, state media confirm.
The Brotherhood candidate, Mohammed Mursi, has a slight lead on former PM Ahmed Shafiq, with a reported 25.3% of votes against 24.9%.
The two represent forces that have battled each other for decades.
The second round in Egypt's first free presidential polls is on 16-17 June.
Voting in the first round took place peacefully on Wednesday and Thursday.
The official results will be announced on Tuesday, but state media have been reporting tallies from polling stations around the country and have now confirmed the two front-runners.