A 45-year old man collapsed and died on Friday while working in a field in the northeast of the country, while another 60-year-old man died of a heart attack in the street in an eastern port on Thursday.
Meteorologists have issued a “red code” heat alert for Saturday, with soaring temperatures expected to subside only after sunset.
Temperatures in the capital Bucharest were forecast to reach up to 40 degrees Celsius (104 degrees Fahrenheit).
Police banned heavy traffic on major roads in daylight hours during the weekend because of the heat wave, while trains were going slower due to the heat.
Authorities have told people not to go outside during peak hours and urged adults not to leave children in cars in the scorching weather.
The heat wave is expected to last until the middle of next week.