Marek Stachowski is a laureate of many composition competitions, such as:
- International „Gaudeamus” Foundation Composition Competition (1968, for Musica con una battuta del tam-tam);
- the Artur Malawski Competition (1968, 1st prize for the same work);
- International Competition of the Solidarity Committee in Skopje (1969, for Chant de l'espoir);
- the Karol Szymanowski Competition (1974, 1st prize for II String Quartet). Moreover, his compositions were twice recommended at the UNESCO International Rostrum of Composers in Paris (in 1979 for Divertimento and in 1990 for II String Quartet).
- In 1976 he received the Mönchengladbach City Music Award;
- in 1979 - the Cracow City Award;
- in 1981 - the Minister of Culture and Art 2nd degree award for his compositions for children.
- He is also a laureate of the Alfred Jurzykowski Foundation Prize in New York.
- In 1998 he was honored with Ruth and Ray Robinson Foundation Excellence in Teaching Prize (USA).