The Sonata for Tuba and Piano was commissioned by Scott Irvine through the financial aid of the Ontario Arts Council. Mr. Irvine suggested to Morawetz the idea of writing a work for his instrument when he was still a student at the Faculty of Music at the University of Toronto but is was only at the beginning of 1983 when the composer got really enthusiastic about this project. Scott brought to the composer's attention the tremendous improvement of tuba players during the last two decades, not only in the facility of fast passages but also in range.

The Sonata is in three movements and each seems to exploit some of the main characteristics of the instrument. The first movement (written in a sonata form) concentrates mostly on the rhythmic flexibility throughout the whole range of the instrument. In the second, very expressive movement, the tuba comes close to the rich colour of a cello. The last lively movement is written in a happy mood, ending exuberantly with a fast coda.