After having a mild fever, Ms. Ana Maslac Plenkovic tested positive on Saturday, the government said in a press release.
The prime minister tested negative afterward, the statement said, adding that he will work from home during the 10-day quarantine.
Croatia registered 3,987 new COVID-19 cases and 55 related deaths in the last 24 hours, the Croatian Institute of Public Health announced on Saturday morning.
Since Feb. 25 when the first case was confirmed in the southeastern European country with a population of four million, over 120,000 people have been infected, while 1,655 have died.
As the world is struggling to control the pandemic, countries across the globe -- among them Germany, China, Russia, the United Kingdom and the United States -- are racing to find a vaccine.