Final results in Armenia indicated incumbent President Serzh Sargsyan took 58.6 percent of the vote while Hovannisian had 36.7 percent.
Russia's state news agency RIA Novosti reports the former foreign minister issued a challenge in Armenia's constitutional court Monday disputing the results.
Hovannisian was involved in demonstrations in Yerevan protesting the outcome since preliminary results suggested a Sargsyan victory in late February.
In 2008, opposition leaders in Armenia called for protests in Yerevan citing irregularities in the presidential elections. An international election observation mission expressed similar concerns over the February vote, saying that while the election was calm and orderly, there were signs of interference at the polls, primarily by supporters of Sargsyan.
The European Union said it was concerned about the latest election, citing "claims of misuse of administrative resources, unclear interpretation of campaign financing provisions and cases of pressure on voters."