A total of 642,859 people voted for Sarkisyan, who is also the chairman of the ruling republican party.
He nearest rival, Armenia's first president Levon-Ter-Petrosyan, received 21.5% of the vote and ex-parliamentary speaker Artur Bagdasaryan 16.7%.
Vaan Ovannisyan, a deputy parliamentary speaker and a member of the Dashnaktsutyun party's bureau, garnered 6.2%.
According to Armenia's election legislation, the winner will be officially declared in a week.
Voter turnout was 69.26%.
An Armenian opposition leader, Nikol Pashinyan, complained that the country's election authorities and international observers ignored reports about election violations.
A total of 14,000 observers from 39 local and six international organizations monitored the elections.
