St. Barnabas maintains a high quality of worship and music, and the choir plays a central role in offering dignified service to God. Week after week, the choir, supported by the fine Casavant organ, sings the praise of God from the gallery, which allows for a remarkable musical presence. Under the direction of highly respected organist and choirmaster Wesley R. Warren, the choir presents a diverse range of sacred music. Within the Anglo-Catholic tradition of plainsong (normally sung in English, but occasionally in Latin), the choir's repertoire continues to represent a wide cross-section of traditional music from Renaissance polyphony (mass and motet settings by Palestrina, Victoria, Monteverdi, Byrd, Tallis, di Lasso, et al.) to contemporary compositions (Willan, Howells, Bissell, Daley, Gjeilo, Ešenvalds, and Warren, among others).
For hymns at choral services we use The Book of Common Praise (revised, 1938), occasionally supplemented by The English Hymnal (new edition, 1933). Gradual Psalms are sung from The Canadian Psalter (Plainsong Edition, 1963), edited by Healey Willan, and the minor propers of the Mass are sung from The English Gradual, Part 2, edited by Francis Burgess. Congregational settings of the Mass (Proper) include: Service of Holy Communion - John Merbecke, Missa de Angelis - Plainsong, and Missa de Sancta Maria Magdalena - Healey Willan.