"Since February 24, a total of 8,403,000 people have crossed into Poland from Ukraine," it said in a tweet.
On Wednesday, around 21,000 refugees from Ukraine arrived in the country, according to the Polish Border Guard.
Meanwhile, more than 6.57 million people have left Poland for Ukraine since February 24, the agency also reported.
On Wednesday, around 18,600 people crossed from Poland into Ukraine, the Polish Border Guard said.
A Polish deputy prime minister said last week that his country was "currently home to more than 2 million Ukrainians."
Poland in March enacted a measure to offer wide-ranging support to Ukrainians escaping the Russian invasion of their country, which began on February 24.
The measure grants them residence rights and ensures access to education, healthcare and social benefits.
Eighty-three percent of Poles are in favour of accepting refugees from war-torn Ukraine, according to a recent survey.
(gs)
Source: PAP