The article analyses W. A. Mozart’s Concert A-dur (К. 622) as a composition representing the process of evolution of concert for clarinet and orchestra in the XVIII century. The authors’ attention is focused on the problem of the concert for clarinet and orchestra genre development, its evolution from J. Molter’s baroque concerts and early classical clarinet concerts of Mannheim school composers (Johann and Carl Stamitz) towards mature classical concert in W. A. Mozart’s creative work. The following aspects of the genre development are analysed: compositional and dramaturgic peculiarities, technical and expressive potential of solo clarinet, interaction of soloist and orchestra.