The exit poll by Ipsos shows Law and Justice won 39.1% of yesterday’s parliamentary vote.
If confirmed by official results, which are expected to be made known today, that would give Law and Justice 242 seats in the 460-seat lower house of parliament, allowing it to govern alone.
That would mark the best showing yet for the party in a parliamentary election.
According to the exit poll, Civic Platform would secure 133 seats and only three other parties would make it into parliament: a party led by rock star Pawel Kukiz, a new pro-business party named Modern Poland, and the Polish Peasants Party.
Voting stations across the nation of 37m people opened at 7am and closed at 9pm.