Orlando di Lasso is regarded as one of the great polyphonic masters of the Renaissance. An international composer of both sacred and secular music, his sacred works have always held an important place in the choral repertory. Especially significant are Lasso's Parody Masses, which comprise the majority of settings in this genre. The "Missa Ad Imitatiomem Moduli Doulce Memoire" and its model, the chanson "Doulce Memoire" by Sandrin, have been selected as the subject of this lecture recital. In the course of this study, the two works have been compared and analyzed, focusing on the exact material which has been borrowed from the chanson. In addition to the borrowed material, the longer movements, especially the Gloria and the Credo, exhibit considerable free material. This will be considered in light of its relation to the parody sections. Chapter One gives an introduction to the subject of musical parody with definitions of parody by several contemporary authors. In addition, several writers of the sixteenth century, including Vicentino, Zarlino, Ponzio, and Cerone are mentioned. Chapter Two relates biographical information on Lasso and gives a brief summary of his compositions. Attention is given to the number and type of Parody Masses by Lasso. Chapter Three discusses Sandrin and the chanson model, "Doulce Memoire." The original French text, an English translation, and form of the chanson are given. Chapter Four gives a detailed analysis of the "Missa Doulce Memoire" illustrating the use of borrowed material on specific sections of the Mass. The free sections of the Mass are discussed and compared with the parody sections. Other compositional devices, such as text painting, varied textures, and coloration are also mentioned. In Chapter Five, the "Missa Doulce Memoire" is compared to Lasso's other parody works and conclusions will be drawn concerning the composer's choice of material and treatment of the text, especially with regard to the free sections, the place of the Parody Mass in Lasso's ouevre. and their place in the modern choral repertory.