At a press conference in Cairo, Mr El Tantawy told supporters that he had not been able to gather the 25,000 endorsements necessary to qualify as a candidate in the election, set to be held in December.
Presidential hopefuls in Egypt must collect either 25,000 popular endorsements from citizens in at least 15 of the country's 27 provinces. Support from at least 20 sitting lawmakers can be a substitute for the 25,000 endorsements.
One of Egyptian President Abdel Fattah El Sisi’s staunchest critics, Mr El Tantawy’s, in a campaign statement on Friday, asserted that he was not able to collect the necessary endorsements because of an “institutional obstruction”, reiterating claims made in September that supporters were being barred from notary offices all over the country.
“I am not withdrawing and we will never withdraw,” Mr El Tantawy said. “It’s only a matter of time before the rule of this regime ends and we can start anew.”
Dozens of El Tantawy supporters posted videos on social media in September recounting how they had been harassed and made to wait for hours while attempting to file their endorsements – which in the end, they were largely not able to do.
Mr El Tantawy then began to hold campaign visits at notary offices in a bid to pressure them to allow his supporters to file endorsements, but to no avail.
The state’s election commission launched an investigation into Mr El Tantawy’s claims and found no evidence of foul play, saying delays in filing endorsements were due to technical malfunctions at notary offices nationwide.
However, Mr El Tantawy said on Friday that there were more than 25,000 people employed by his campaign, pointing out that endorsement from his volunteers alone would have been enough to qualify him.
Gamila Ismail, another popular opposition candidate and head of the leftist Al Dostour party, announced her withdrawal from the presidential race on Wednesday. She had announced her intention to run last month.
Ms Ismail said that her party’s high council had decided to refrain from putting forth a candidate for the presidential race.
Mr El Sisi filed his bid for election earlier this month after receiving 1.13 million endorsements and support from 424 parliamentary seats.
Hazem Omar, head of Egypt’s Republican People's Party, filed his bid for the presidential race with the election commission on Friday. Mr Omar was able to collect a little more than 68,000 citizen endorsements in addition to support from 31 parliamentary seats.