The Polish Roman Catholic church heirarchy called on compatriots on Wednesday to vote for "Christians and Catholics" when the country takes part in European Parliament elections for the first time in June.
"The presence within this important assembly of Christians, Catholics, people who stand for high moral values, is even more important today, as strong trends aimed at wiping Christian values out of the lives of European people appear," Polish bishops said in their appeal.
Poland, one of 10 mainly ex-communist countries to join the European Union on May 1, will elect 54 representatives to the 732-seat assembly.
The church urged Poles to turn out and vote on June 13, warning against opting for those who "attack human life and the family."
More than 90 percent of Poles say that they are Catholic, but among some of the left-wing candidates to the European Parliament are some supporters of a liberalisation of Poland's strict anti-abortion law.
"The bishop's conference strongly protested and continues to protest against the legalisation of abortion and that of euthanasia, as well as against homosexual partnerships whose legalisation would attack the very essence of the institution of marriage and the family," the bishops said.
In their letter to worshippers ahead of the EU's enlargement the bishops reiterated their demand for a reference to Christian values in the preamble to a future European constitution.