The Sixth, Seventh, and E Piano Sonatas of Prokofiev illustrate the composer's more mature style. In these works there is a definite return to the classic forms and contrapuntal devices which have been called Neo-classicism. Prokofiev, himself, has said that form is one of the basic elements of his style. It is the purpose of this thesis to discover the' formal organization and make a comparison of these sonatas with the works of Beethoven and his contemporaries.