Chicago Master Singers (CMS), under the direction of Alan Heatherington, is a 130-voice choral ensemble featuring accomplished singers from Chicago and suburban communities. CMS has performed great choral masterworks in collaboration with professional soloists and orchestras since 1979.

CMS was founded in 1979 as The New Oratorio Singers (TNOS), by which name it was known until the end of the 1999-2000 concert season. The motivation for its formation was a desire to give auditioned singers an opportunity to perform large-scale choral works with professional soloists and orchestra. Its goal was to present concerts in northwest suburban Chicago communities and thus bring great music to audiences outside the cultural center of the city.

Since its founding, CMS has successfully fulfilled that goal, having performed in Johnsburg, West Dundee, Woodstock, Lake Zurich, Inverness, and Barrington. In recent years, additional venues have included Evanston, Chicago, Mundelein, and Techny. Divine Word Chapel at Techny in Northbrook has become a regular performance location.

In 1993, members of the ensemble participated as the featured chorus at the International Church Music Festival in Oberammergau, Germany. While on tour, the chorus also gave concerts in Munich, Salzburg, and Innsbruck. In June of 1996, they participated in a private tour of England with scheduled performances throughout Britain. In July of 1998, the chorus toured Prague, Budapest, and Vienna, performing to packed houses in many historic and beautiful churches in those cities.

Following its twenty-first season, the chorus changed its name to Chicago Master Singers and embarked on a tour of France, Switzerland, and Austria, performing as the featured chorus in the inaugural Innsbruck International Choral Festival in June 2000. The chorus continues to tour in Europe in alternate years, with tours to Italy in 2002, to the Czech Republic and Germany in 2004, and most recently to Poland, France and again Germany.

CMS concerts have included such major works as Brahms' Ein Deutches Requiem, Mendelssohn's Elijah, Haydn's Creation, Verdi's Requiem, and works of Mozart, Rachmaninoff, Faure, Bruckner, Kodaly, Vaughan Williams, Dvorak, John Rutter, and other great composers. The chorus collaborated with the Chicago String Ensemble in presenting Bach's St. Matthew Passion and Christmas Oratorio. CMS's twentieth anniversary season presented Mozart's Requiem and Bach's St. John Passion.

CMS performs with professional soloists and orchestras who perform with the Ars Viva! Symphony Orchestra, the Chicago Symphony Orchestra, the Lyric Opera Orchestra, and numerous other orchestra and concert groups. In the past, CMS has received grants from the Barrington Area, Lake County, and Illinois Arts Councils.

CMS is an auditioned chorus.  Its members are from more than 30 communities and come from all walks of life and professions. For some, music is their vocation as teachers and choir directors, but for many others it is their avocation, a way to enrich their lives by coming together with others who love to sing and perform the works of the masters.