The bill, sponsored by liberal MP Crin Antonescu and social democrat MP Victor Ponta, was adopted with 180 to 30 votes, with 26 abstentions. It says the winning candidates in every constituency will become deputies and senators, and in counties where national minorities make up more than 7% of the population, they will receive an extra MP seat.
The election threshold, currently 5%, has been eliminated.
The Chamber rejected an amendment filed by the Democratic Liberal Party to reduce the number of MPs to 300.
The debates were marked by protests against the bill from non-governmental organizations.
Since the Senate has already adopted this bill, it will be sent for promulgation to President Traian Basescu.