Sonata for Horn and Piano was commissioned in 1977 by the Canadian Broadcasting Corporation at the suggestion of Eugene Rittich, the principal horn of the Toronto Symphony. He premièred it with Patricia Parr at the piano May 15, 1980. This performance was broadcast the following year on April 2, 1981.

The first movement is an expressive Adagio; it is a free fantasy, though the first two themes return in the last section of the movement. The opening theme is brought back at the dynamic climax in the bass of the piano while the second theme dies away as if from a distance at the end of the movement.

The second movement is fast and could be called a Scherzo. It is mostly in 3/8, 6/8 and 9/8 metre. It is very rhythmic in character even in the very low register of the horn in the middle of the movement. But it also contains florid passages in 16th notes reminiscent of semi-tone trills, as well as the strking colour of open notes sliding by semitone to muted notes toward the end of the movement.

The third movement starts with a slow expressive melody in the piano which is continued by the horn. After a varied second statement, a dreamy mysterious section follows which gradually rises in volume and pitch to the high E-flat of the horn. From there, the melodic line of the horn falls until it reaches a soft sustained low F. There the piano takes over, playing softly the opening bars. But this quiet mood is suddenly interrupted by a trill in the horn which ends with a crescendo on a loud muted note at which point the trill is taken over by the piano. This short motif is repeated twice and leads back to the dreamy section which forms the coda of this movement.

The last movement is an Allegro of great contrast and rhythmic vitality. It contains many changes of metre including the uneven 5/8 and 7/8. The coda could be described as a long development of all the preceding themes, steadily rising in power and excitement.

Program notes from Michael Nunes:

Sonata for Horn and Piano was commissioned by Eugene Rittich - former principal horn of the Toronto Symphony Orchestra - and the Canadian Broadcasting Corporation. The sonata is characteristic of Morawetz' approach to technique, harmony, and form. Though extended techniques had entered the vernacular of the twentieth century hornist, Morawetz rejected the avant-garde expectations of twentieth century composers and instead utilized traditional techniques such as hand stopping and muting. While dissonant and angular, the harmonic language of the sonata is undeniably tonal. Instead of relying on traditional forms, the work is generated from short melodic cells which develop organically over the course of the four movements. Each movement encompasses a wildly different character, from a hazy prelude, to a light-footed dance, to a series of cadenza-like passages, and finally a fiery and percussive ending.