Temperatures as low as minus 23 degrees Celsius and heavy snowfall this month have left the capital Kiev and most of the country under a thick frozen layer.
In the western part of the country, vehicles were trapped in a three-day traffic jam stretching at one point about 20 km.
The severe weather is also affecting neighbouring Bulgaria and Romania, where six people have reportedly died.
An official from Ukraine's health ministry said 83 people were known to have died from the cold. Most of the victims had been found on the streets.
More than 500 people were being treated in hospitals across the country.
Nearly 100 towns and villages across the country remain without electricity. Army units have also been deployed to help clear the snow on major motorways.
Thousands of "heating shelters" have been set up where the homeless and the elderly can get a hot meal and a warm place to sleep.
Last winter, more than 100 people died from the cold in Ukraine.