Deputy head of the Muslim Brotherhood, Egypt's strongest political movement, and thus a top contender. A behind-the-scenes operator, el-Shater, 61, is the top Brotherhood strategist and a chief financier.
Educated as an engineer, el-Shater is a multimillionaire, owning or running a network of businesses, including investment companies, manufacturers and a furniture chain.
El-Shater spent 12 of the past 20 years in prison under then-President Hosni Mubarak's crackdowns on the Brotherhood. He was released from his latest stint after last year's anti-Mubarak uprising and was pardoned by the ruling military.
The Brotherhood calls for an "Islamic basis" for Egypt's government. El-Shater touts his "Renaissance Project" aimed at modernizing long corrupt and incompetent institutions including education, agriculture, transportation and health care.
Formerly the top reformist within the Muslim Brotherhood, which led to clashes with its conservative leadership. The 60-year-old Abolfotoh was ousted from the group last year when he announced his presidential bid, defying the Brotherhood's decision at the time not to field a candidate - a promise it later broke anyway by fielding el-Shater.
Abolfotoh has stood out from the Brotherhood by promoting a more inclusive and open vision. As a result, he is popular among pro-reform Brotherhood youth. In his campaign, he seeks to appeal to moderate Muslims and Egyptians wary of both Mubarak-era officials and hard-line Islamists. A religious conservative, he emphasizes democratic reform over an Islamist agenda.
HAZEM ABU ISMAIL
A lawyer turned television preacher who emerged as a favorite of ultraconservative Islamists known as Salafis. Abu Ismail, 50, has mirrored their calls for implementing a strict version of Islamic law, similar to Saudi Arabia's, with segregation of the sexes and enforcement of public morality. He has also gained support through his denunciations of military rule.
Salafi support makes Abu Ismail a strong rival of el-Shater. But he is very likely to be disqualified by the election commission after it confirmed his mother received American citizenship briefly before her death. Election rules bar any candidate whose spouse or parents hold foreign nationality.
FORMER REGIME FIGURES:
One of the most powerful figures in Mubarak's inner circle, serving as his intelligence chief since 1993.
Beyond intelligence duties, Suleiman was entrusted with running Egypt's most important relationships - with the U.S., Israel and the Palestinians. His intelligence agencies were key to maintaining domestic security, and he is believed to have played a direct role in the United States' "rendition" program, in which terror suspects were sent to allies like Egypt for interrogation - often under torture.
A secretive figure, Suleiman was rarely seen in public. He took an unusually public profile when Mubarak named him vice president during last year's 18-day uprising. It was Suleiman who announced Mubarak's resignation on state TV on Feb. 11.
In his presidential bid, the 75-year-old Suleiman says his priorities are to re-establish security and rebuild the economy. He is believed to be running with the support of the ruling military.
One of the more popular politicians of Mubarak's regime, serving as foreign minister for decade before becoming Arab League secretary-general in 2001. One reason for his popularity was his vocal criticism of Israel. One singer even put out a tune called, "I Love Amr Moussa and I Hate Israel," which became a big hit. Some believe the song prompted Mubarak, worried over a possible rival, to move Moussa to the Arab League.
Moussa, 76, is of secular background and backs good ties with the West. He is positioning himself as an elder statesman. For revolution supporters, he bears the taint of his regime ties, but in the eyes of others his past frictions with Mubarak give him a distance from his former boss.
A former Air Force commander and civil aviation minister who briefly served as prime minister in the last days of Mubarak. Shafiq, 70, was replaced less than month after Mubarak's Feb. 11 fall, amid protests over a regime figure holding the prime minister post.
A 40-year-old human rights lawyer and anti-corruption advocate who has spoken out against the handling of Egypt's transition by the military rulers and has taken part in strikes for workers' rights.
He is the closest candidate in ideology to the young, liberal and leftist activists who launched the anti-Mubarak uprising. But he is hardly known by the general public and several activists have said they will not back him since he is not a real contender.