Mukwege, who won the award in 2018 for his nearly two-decade fight against sexual violence, made the announcement to a jubilant crowd of supporters at a conference centre in the capital Kinshasa.
Nicknamed the "man who repairs women", the 68-year-old doctor has treated hundreds of war rape victims at the Panzi Hospital he founded in conflict-ridden east Congo in 1999.
He will be running against President Felix Tshisekedi, whose first term was mired by economic hardship, epidemics and worsening insecurity in the east, where the M23 rebel group launched a major offensive last year.
Opposition leader Martin Fayulu, who came second to Tshisekedi in the last vote 2018, said over the weekend he would be running.
(Reporting by Ange Kasongo, Sonia Rolley and Crispin Kyala; Writing by Sonia Rolley; Editing by Sofia Christensen and Andrew Heavens)
