Carl Frederick Mengeling S.T.D (born October 22, 1930) is an American prelate of the Roman Catholic Church.

[1] In 1961, Mengeling entered the Pontifical University of St. Thomas Aquinas in Rome, obtaining his Licentiate of Sacred Theology.

Raised by the Vatican to the title of monsignor in June 1984, Mengeling chaired the Diocesan Worship Commission and the Vocations Committee in Gary.

Mengeling also served on the Presbyteral Council, the Ecumenical Commission and the Permanent Diaconate Formation team.

[1] On November 7, 1995, Pope John Paul II appointed Mengeling as the fourth bishop of the Diocese of Lansing,[2][3][4] He received his episcopal consecration on January 25, 1996, from Cardinal Adam Maida, with Bishops Kenneth Povish and Dale Melczek serving as co-consecrators, in St. Mary Cathedral in Lansing, Michigan.

The diocese forwarded the accusation to the Genesee County Michigan district attorney and asked the Vatican to defrock DeLorenzo.