Traditional cab operators have already staged protests in Brussels, Lisbon and Paris this year, the latter turning violent.
They argue that the app represents unfair competition because Uber drivers can flout the rules and restrictions that regulate professionals.
Sporting little red-and-white national flags, the taxis crawled through Warsaw at 30 kilometres (20 miles) an hour before converging on parliament. Organisers said 2,000 drivers took part.
"We're protesting against unfair competition from companies that don't pay taxes and take away our livelihood," a driver for the ELE taxi service told AFP.
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It has been operating in Warsaw since last year and is also present in the northern city of Gdansk and the southern city of Krakow.
But it is just one of many such companies on the market, prompting Poland's cab drivers to call for legislation aimed at the firms.
Parliament has a bill in the works that would require transport companies to establish their tax residence in Poland -- currently not the case for Uber -- and employ licensed taxi drivers.
Anticipating such court decisions, Uber has launched an upmarket alternative service called Uber X in several European markets which requires professionally licensed drivers.