Casimir J. Grotnik (1935–2005) was a priest and bishop of the Polish National Catholic Church (PNCC).
He was ordained a priest on April 20, 1958, by the bishop of Lublin, Piotr Kalawa.
Grotnik immigrated to the United States in 1969 and served as a priest in the Central Diocese of the Polish National Catholic Church.
From that point, he served as the bishop ordinary of the Central Diocese and the pastor of St. Stanislaus Polish National Catholic Cathedral in Scranton, Pennsylvania, until his death on December 9, 2005.
This article about an individual bishop of a bishopric from the United States is a stub.