This study explores the notion of Johann Sebastian Bach`s stile antico, and its role in his Mass in B minor, arguing that stile antico plays a fundamental role in appreciating and understanding Bach`s sacred vocal music, in particular, the Mass in B minor. In order to illustrate the role that the stile antico plays in those three movements of the second Kyrie, Credo, and Confiteor in the Mass, this study first attempts to define the stile antico. By critically reviewing the current study on the notion, this study proposes that the definition of the stile antico needs to be expanded as to include the association between Bach`s stile antico and his notation that is partially based upon the mensural system of the Renaissance period. After analysing the stile antico movements from the Mass, this study proposes that Bach`s stile antico needs to be understand both a musical style and compositional procedure and the composer`s attitude toward the musical tradition of the past.