Paruir Airikian, 63, was shot Thursday near his home in Yerevan, the Armenian capital, RIA Novosti reported.
Airikian was reported in stable condition, Novosti-Armenia news agency said. His doctors said surgery to remove the bullet early Friday was successful, and the candidate was under anesthesia.
The head of the Union for National Self-Determination, Airikian is one of eight candidates running in the presidential election set for Feb. 18.
Political analysts have said President Serzh Sargsyan is expected to win a second term, EurasiaNet.org reported. Airikian polls at less than 5 percent.
Airikian began his political career as a dissident when Armenia was a Soviet republic. He has been the target of a number of assassination attempts in the past.