Thaddeus Lewis Biernat (October 27, 1918 – August 1, 1996) was an American businessman and politician.
He graduated from Edison High School in Minneapolis in 1936.
Biernat served in the United States Army during World War II.
Biernat served in the Minnesota House of Representatives from 1949 to 1956 and was a Democrat.
His son Len Biernat also served in the Minnesota Legislature.