EU flag burned as tens of thousands join Warsaw nationalist demo
Organisers said that up to 50,000 were on the march which marked the anniversary of Poland's independence after the Second World War
"Yesterday it was Moscow, today it's Brussels which takes away our freedom," chanted one group of protesters.
Other banners read "Great Catholic Poland" and "Stop Islamisation".
Several thousand riot police officers were deployed for the protest, which was punctuated by numerous firecrackers and smoke bombs but otherwise went off peacefully.
The annual march, organised by Poland's nationalist right, has seen clashes in previous years.
"I came here because I love Poland and want to show it," said 27-year-old Piotr, who came with his fiancee. He added: "I came here for my grandfather, who fought in the Warsaw Uprising (against the Nazi occupation of the Polish capital), and for his father, who fought for independence".
Poland is returning to conservative rule after eight years of centrist government, following the Law and Justice (PiS) party's landslide election victory last month on a platform playing strongly on fears over the European migrant crisis.