The government launched its Covid-19 vaccination campaign on Tuesday morning using Sputnik V shots developed by Russia.
Argentina is the first country in the Americas to use this vaccine against the pandemic.
The vaccination drive began simultaneously around the country with frontline healthcare workers given priority, Health Minister Ginés González García confirmed to reporters.
Those aged over 60, who suffer risk factors, teachers and the police will also head the queue.
The minister spoke to the press at Posadas Hospital in El Palomar, Buenos Aires Province, where a nurse named Flavia Loiacono became the first in the country to get a Covid shot.
Shortly afterwards, Buenos Aires Province Governor Axel Kicillof became the first high-level politician to receive a dose at La Plata's San Martín hospital
Argentina is now the fourth country in Latin American to launch a vaccination campaign against Covid-19, after Mexico, Costa Rica and Chile.
"We are going to have to keep taking care of ourselves. It will take a few months for the vaccine to have a widespread effect," González García said.
"The idea is to start vaccination with those who have more exposure to risk factors," added the minister.
The Gam-CovidVac vaccine, nicknamed Sputnik V after the Soviet-era satellite, has come under fire from critics in Russia and abroad because it was registered before the start of large-scale clinical trials. Its developers claim it is more than 90 percent effective but detractors have described it as a tool to bolster Russia's geopolitical influence.
A first shipment of 300,000 doses of the Russian product arrived in Buenos Aires on Christmas Eve. It requires people to get two shots, with the second coming 21 days after the first. Another 19.7 million doses are supposed to be delivered in January and February.
Buenos Aires Province, the nation's most populous, has received about 40 percent of the initial 300,000 doses. An online registration service has been launched by the regional government through which residents can apply. As of Monday afternoon, around a quarter of a million people had signed up.
Argentina has also signed an agreement to obtain doses of the vaccine developed by Oxford University and AstraZeneca, and is negotiating with Pfizer-BioNTech, though talks over the latter have reportedly stalled.
The pandemic has killed nearly 43,000 people in Argentina, with more than 1.55 million confirmed cases. The Alberto Fernández administration plans to acquire a total of 51 million vaccine doses.