Airikian was shot outside his house in the Armenian capital, Yerevan, just before midnight. A neighbor who heard gunshots and cries for help called the police.
Airikian is one of eight candidates in the Feb. 18 presidential vote, which incumbent Serge Sarkisian is expected to easily win. Recent opinion surveys show Airikian getting just over 1 percent of the vote.
Yerevan Clinical Hospital's chief doctor, Ara Minasian, confirmed that the 63-year-old Airikian was being treated for a single gunshot wound and remained in stable condition.
Eduard Sharmazanov, a deputy speaker of parliament who is a member of the ruling Republican Party, described the attack on Airikian as a "provocation against democratic, free and transparent elections."
Armenian parliament speaker Ovik Abramian, who visited Airikian at the hospital, said the attack on the candidate could be an attempt to thwart the election. He said the vote could be postponed if Airikian's condition prevents him from taking part in the race, but the nation's election chief refused to comment on the possibility.
Armenia's constitution requires the vote to be postponed for two weeks if one of the candidates is unable to take part due to circumstances beyond his control. It envisages a further 40-day delay if the problem isn't solved.
The Armenian presidency is an important position with broad executive powers, and the campaign for the job has been marked by much tension. Airikian, a Soviet-era dissident, briefly joined a hunger strike by another candidate over procedural issues related to the vote.
This landlocked, overwhelmingly Christian nation of 3 million has faced severe economic challenges caused by the closing of its borders with Turkey and Azerbaijan in the wake of a territorial conflict.
The Nagorno-Karabakh region of Azerbaijan and some adjacent territory has been under the control of Armenian troops and local ethnic Armenian forces since a six-year war ended with a truce in 1994. But international efforts to mediate a settlement have brought no result.
Armenia's politics have been tense and often mired by violence. In 1999, six gunmen burst into parliament and killed the prime minister, parliament speaker and six other officials and lawmakers. Nine people were wounded. The attackers said they were driven by a desire to save the country from economic collapse and official corruption. They were sentenced to life in prison and one later commited suicide.
Airikian was a dissident during the Soviet times. He was first arrested when he was 20, sentenced to four years in a prison camp and later received another two-year sentence. In 1987 after Soviet leader Mikhail Gorbachev launched his liberal reforms, Airikian created the National Self-Determination Party. When the conflict between Armenia and Azerbaijan erupted next year, he accused the Soviet authorities of stirring up violence and was evicted from the country.
Airikian soon returned to his country and took senior positions in Armenia's parliament and government in the 1990s. He ran unsuccessfully for president in 2003.