Culture Minister Bogdan Zdrojewski gave the pictures back to the museum in a ceremony at the ministry on Tuesday.
The masterpiece watercolor "Off to the Hunt" and an oil picture "The Hunt" are by 19th century artist Julian Falat, known for his hunting and landscape scenes. U.S. authorities handed them over to Polish officials in New York last month.
They were seized last year during an investigation after Polish authorities alerted the U.S. that both were about to be sold at auction.
They had been missing since 1944.