Polling stations will open at 7 a.m. and close at 9 p.m.
The ballot will be held at 31,497 polling stations in 41 electoral districts across the country. Some 29 million Poles aged 18 and over are eligible to vote.
A media blackout began on Friday at midnight under which domestic news organizations are prohibited from publishing opinion polls showing the level of support for political parties.
The ban lasts until polling stations close. Political campaigning is also forbidden during this period.
More than 600,000 Poles living abroad have registered to vote by absentee ballot, according to the Polish foreign ministry.
The official results of the election are expected to be announced by Tuesday.
Sunday's parliamentary vote will be combined with a referendum on issues including migration and the retirement age.
(gs)
Source: Polish Radio, IAR, PAP, wybory.gov.pl