The 73-year-old leader had been widely expected to seek a second five-year term in the troubled Sahel nation.
The election is set for July 29, with a second round planned for August 12 if no candidate obtains an absolute majority of votes.
Keita will face around a dozen challengers, including Modibo Kone, a rural development expert at the West African Development Bank, and Hamadoun Toure, who runs the "Smart Africa" initiative to drive development on the continent via technology.
Planned elections have been repeatedly postponed since 2013, in part because of security concerns over Islamist extremism.
Jihadists linked to Al-Qaeda took control of the desert north of Mali in early 2012, but were largely driven out in a French-led military operation launched the following year.
Mali's army, French soldiers and a UN mission still have little control over large tracts of the West African country, which regularly comes under attack despite a peace accord signed in May and June 2015 with the aim of isolating the jihadists.
The past two years have seen Islamist attacks spread to central and southern areas as well as over the border into neighbouring Burkina Faso and Niger.
Regional elections, already pushed back from December to April, were again postponed in March to the end of 2018.