President Cristina Fernandez has been re-elected in a landslide, winning with the widest victory margin in Argentina's history after her government spread the wealth of a booming economy.
Ms Fernandez had 53% of the vote after 58% of the polling stations reported nationwide. Her nearest challenger got just 17%.
Interior minister Florencio Randazzo predicted the president's share would rise as polls reported from her party's stronghold of densely populated Buenos Aires province.
"Count on me to continue pursuing the project," Ms Fernandez vowed in her victory speech. "All I want is to keep collaborating ... to keep Argentina growing. I want to keep changing history."
Ms Fernandez is Latin America's first woman to be re-elected as president, but the victory was personally bitter sweet - the first without her husband and predecessor, Nestor Kirchner, who died of a heart attack last year.
"This is a strange night for me," she said, describing her mix of emotions. "This man who transformed Argentina led us all and gave everything he had and more ... Without him, without his valour and courage, it would have been impossible to get to this point."
Thousands of jubilant, flag-waving people crowded into the capital's historic Plaza de Mayo to watch on a huge TV screen as she spoke from a hotel, where her supporters interrupted so frequently with their chants that she lectured them as a mother would her children: "The worst that people can be is small. In history, you always must be bigger still - more generous, more thoughtful, more thankful."
Then, she showed her teeth, vowing to protect Argentina from outside threats or special interests.
"This woman isn't moved by any interest. The only thing that moves her is profound love for the country. Of that I'm responsible," Ms Fernandez said.
Later, she appeared in the plaza as well, giving a rousing, second victory speech, her amplified voice echoing through the capital as she called on Argentina's youth to dedicate themselves to social projects nationwide.