This year's March for Life and Family in the Polish capital aimed to highlight the role of marriage in society.
Participants called for traditional Christian values to be upheld while opposing same-sex marriages, broadcaster TVP reported.
Marchers appealed to authorities to "take action to help save marriages from divorce" and called for "solutions to help strengthen marital ties," warning that divorce harms families, state news agency PAP reported.
The march was "a response to the crisis afflicting marriage and family," according to Paweł Ozdoba, a spokesman for the organizers.
He said the annual march, now in its 17th year, sought to promote the view that "marriage is a union of a woman and a man" and "an important institution that builds society."
President Andrzej Duda issued a special message to those taking part in the event, voicing support for their cause.
He said in his message that "a strong family is the foundation of prosperity in the country."
Source: PAP, TVP, prezydent.pl