Vice-presidential running mates: Mohammad Khan (Pashtun) (left in photo), Mohammad Mohaqeq (Hazara) (right in photo)
Abdullah (born in 1960) is a former foreign minister and qualified eye surgeon. He finished second behind President Hamid Karzai in the 2009 presidential election, with around 30 percent of the vote.
The Jamiat-e Islami and Hezb-e Islami were deadly rivals during Afghanistan's civil war, but that did not prevent Jamiat-e Islami member Abdullah from adding Hezb-e Islami associate Khan to his ticket.
Ashraf Ghani
Pashtun
Vice-presidential running mates: General Abdul Rashid Dostum (ethnic Uzbek), Sarwar Danish (Hazara)
Ghani (born in 1949) is a former finance minister and World Bank official who has a doctorate in cultural anthropology.
The Western-educated technocrat fared poorly in the 2009 election, coming in fourth place with only three percent of the vote
He raised eyebrows after partnering up with Dostum, a notorious former warlord who has been implicated in numerous human rights violations.
Zalmai Rasul
Pashtun
Vice-presidential running mates: Ahmad Zia Masud (ethnic Tajik) and Habiba Sarabi (Hazara)
Rasul (born in 1944), a former foreign minister, is seen by many as the president’s favored candidate.
He hails from the powerful Mohammadzai tribe in the country's south that has ruled Afghanistan for most of the past century.
Rasul is a soft-spoken man who has kept a low profile during his time as a presidential adviser and minister.
Abdul Rasul Sayyaf (center)
Pashtun
Vice-presidential running mates: Ismail Khan (ethnic Tajik) (left in photo) and Abdul Wahab Erfan (ethnic Uzbek) (right in photo)
Sayyaf (born in 1946) is an influential lawmaker from Kabul who is one of the most controversial and conservative of the candidates.
He is an Egyptian-trained cleric who is credited with bringing leading Al-Qaeda figures -- including former leader Osama bin Laden -- to Afghanistan during the Soviet occupation in the 1980s.
Sayyaf’s right-hand man, Khan, is the former energy and water minister. Khan, a former Tajik warlord from Herat Province, is referred to as the emir (or king) of western Afghanistan.
Gul Agha Shirzai
Pashtun
Vice-presidential running mates: Sayed Hossain Alemi Balkhi (Hazara) and Mohammad Hashem Zare (ethnic Uzbek)
Shirzai (born in 1955) is a former governor of both the Kandahar and Nangarhar provinces. His nickname is "The Bulldozer," reflecting his hard-hitting style and reputation for getting things done.
During his time as governor of Nangarhar, the former warlord was praised for completing a series of daunting infrastructure projects in record time, eradicating opium production, and curbing militant activity in the province.
But his record was tarnished by concerns from the international community that he was using his position of power to accumulate personal wealth. He is accused by his opponents of intimidation and extortion.
Hedayat Amin Arsala
Pashtun
Vice-presidential running mates: General Khudaidad (Hazara) and Safia Seddiqi (Pashtun)
Arsala is a prominent politician and former finance minister who was educated in the United States.
Arsala (born in 1942), an economist by trade, has teamed up with General Khudaidad, a former minister of counternarcotics. Arsala's other running mate is Safia Seddiqi, a dual Afghan-Canadian citizen who hails from the eastern province of Nangarhar.
Qutbuddin Helal
Pashtun
Vice-presidential running mates: Enayatullah Enayat (ethnic Uzbek) and Muhammad Ali Nabizada (ethnic Tajik)
Helal is a prominent member of the Hezb-e Islami faction led by notorious jihadist leader Gulbuddin Hekmatyar, who has been blacklisted by Washington as a terrorist.
The Hezb-e Islami, currently fighting against international and Afghan security forces, has been accused of some of the worst human-rights abuses that occurred during Afghanistan's civil war in the 1990s.
Sultanzoi is a former member of parliament from volatile Ghazni Province. The 60-year-old is a technocrat and seen as a reformer. He has been highly critical of President Karzai and the presence of former warlords in the government. Sultanzoi was the head of the Economics Committee in the lower house of parliament before he resigned to run for the presidency.
He is a former United Airlines and Ariana Afghan Airline pilot. Sultanzoi, who has relinquished his German citizenship, has adopted two pens as his election symbol.
Qayum Karzai -- WITHDRAWN
Pashtun
Vice-presidential running mates: Wahidullah Shahrani (ethnic Uzbek) and Ibrahim Qasemi (Hazara)
Qayum Karzai (born in 1957), outgoing President Hamid Karzai's older brother, is a prominent technocrat.
He is also a businessman and former lawmaker. Interestingly, Qayum has not received the backing of his brother.
Qayum was to have run with Wahidullah Shahrani, an ethnic Uzbek who has served as minister of mines, and Ibrahim Qasemi, a Hazara and former member of parliament.
Vice-presidential running mates: Shah Abdul Ahad Afzali (ethnic Tajik) and Sayed Hussain Anwari (Hazara)
Wardak (born in 1940) is a former minister of defense who most recently served as a security adviser to the president.
The U.S.-educated Wardak played a key role in rebuilding the Afghanistan National Army but was sacked after a no-confidence vote by parliament in 2012 over alleged security failures.
During the Soviet occupation of Afghanistan in the 1980s, Wardak led one of the Islamist mujahedin groups fighting the Afghan communist regime and its Soviet backers.
He gave no reason for his withdrawal from the presidential race in mid-March and did not back any other ca
Prince Mohammad Nader Naim -- WITHDRAWN
Ethnic Pashtun
Vice-presidential running mates: Taj Mohammad Akbar (Tajik) and Azizullah Puya (Pashtun)
Naim is the grandson of former King Zaher Shah, who was ousted from power in 1973 and lived in Rome until he returned to Afghanistan in 2002.
Naim, who returned to Afghanistan in 2002 after two decades in exile, was a close aide to the former monarch, who died in Kabul in 2007.
He announced his withdrawal at a press conference on March 26 that was attended by candidate Zalmai Rasul, for whom Naim urged his supporters to vote.