Pictures from a dashboard camera capture the incident during which a car belonging to a Ukrainian journalist was run off the road.
Tatyana Chornovol was driving home when her vehicle was repeatedly rammed by a sports utility vehicle.
Although she tried to reverse out of danger, the SUV followed.
Three men then attacked and beat her.
It is being reported two men have been arrested and a third is being sought.
She suffered a broken nose, concussion and numerous bruises according to an online newspaper and is currently in intensive care.
She is likely to need several operations.
Tatyana Chornovol is famous in Ukraine for her exposés of the lives of the country’s top officials.
She has exposed the affairs of top officials, whom she has accused of engaging in dubious business practices.
Shortly before she was attacked, she wrote in her blog about a country manor which, she claimed, belongs to the Interior Minister.
Last year she managed to post photos of President Yanukovich’s golf course and house boat.
There is no suggestion either man was in any way involved in the attack on Ms Chornovol.
Activists in Independence Square reacted to the beating by calling for picketing at the Interior Ministry in Kyiv.
President Yanukovich has ordered an investigation.