Tens of thousands of Armenians have been holding rival demonstrations in the capital, Yerevan, ahead of a second round of presidential elections on Wednesday.
Kocharyan is said to have brought a measure of stability
Police said that 100,000 people went to hear President Robert Kocharyan, who narrowly missed being re-elected in the first round of voting on 19 February.
People's Party leader Karen Demirchyan - who challenges Mr Kocharyan in the second round - gathered 20,000 people, according to police, in the latest daily protest by his supporters against the first round result.
We must win a convincing victory that no-one can question
President Robert Kocharyan
There were widespread allegations of irregularities both from the opposition and from Western election observers, who said the election "fell far short of international standards".
Mr Kocharyan received 49.48% of the vote compared with Mr Demirchyan's 28.22%.
First round criticism
Monday is the last official day of campaigning before the election.
Mr Kocharyan said the result needed to be clear-cut.
The opposition is complaining about first round irregularities
"We must win a convincing victory that no-one can question," he told supporters at the rally.
Mr Demirchyan continued to attack the conduct of the first round, saying Armenians had to choose between "democracy and dictatorship".
"I might be taking part in the second round," he said, "but that doesn't mean I accept the result of the first."
Mr Demirchyan has declined to take part in a Monday evening TV debate, saying that journalists chosen to ask the candidates questions were biased against him.
Mr Kocharyan's spokesman said the president would answer questions whether or not Mr Demirchyan was there as well.
Mr Kocharyan is credited with bringing a measure of stability to the country.
Energy supplies have been widely restored under his presidency, but poverty is widespread, with average monthly salaries of about $40.
His rival is the son of former parliament speaker Karen Demirchyan - one of eight people killed in a 1999 parliamentary massacre.
Mr Demirchyan won 27.7% of the vote on an anti-corruption platform, capitalising on the popularity of his father, a Soviet-era Communist party boss who lost to Mr Kocharyan in the 1998 election.