The UCIIM is a free association of teachers and of school managers and inspectors. It has no lucrative aims; it is a non-party union and its main function in the school system consists in the professional and vocational training of school operators. The monogram UCIIM preserved the dotted form of U.C.I.I.M. up to 2001 because it was the acronym of Unione Cattolica Italiana Insegnanti Medi (Catholic Union of Italian high school Teachers). In the national convention in 2000 it was decided to adopt an undotted form of the acronym as a symbol of the union because since that year it has enlarged its boundaries to school managers and to the teachers of low school and of vocational training.

The association was founded on 18th June 1944 by Gesualdo Nosengo, an Italian pedagogist, great humanist and committed laical intellectual; a man with great ideals who believed in the values of school and in the "mission" of teachers (G. Nosengo, born in San Damiano D'Asti on 20th July 1906 - died in Rome on 13th May 1968).

The association is made up of hundreds of departments and about 8000 members spread all over Italy. In Sicily, a region in the south of Italy, it has 45 departments. The regional board of governors is made up of 23 members and has its seat in Partanna, a pleasant town in the south-west part of Sicily, not far from Trapani, one of the nine province cities in Sicily.