The governing conservative Law and Justice (PiS) party won 36.8 percent of the vote, while the liberal Civic Coalition (KO) was in second place with 31.6 percent, and the centre-right Third Way alliance was third with 13 percent, according to the survey by pollster Ipsos.
The New Left party was fourth on 8.6 percent, and the far-right Confederation group, with 6.2 percent, also crossed the 5-percent voter support threshold that Polish parties need to clear to enter parliament.
Turnout was a record 72.9 percent, according to the exit poll.
Parties from across the political spectrum have said the election is the most important since the collapse of communism in 1989 and that it would decide the future direction of a country riven by bitter political divisions between conservatives and liberals.
The official election results are expected to be announced by Tuesday.
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Source: IAR, PAP, TVP, TVN24, Polsat News