Matilda Seppälä has composed for orchestra, chamber ensemble and choir, as well as worked in experimental ways. Prominent features of her works are curiosity, learning new things and methods and diving in to the mystery of creation, even when it requires an experimental attitude.

She is interested in the relationship between instrument and body, and has played with bio data sensors, performance art and spatial works with non-linear form. Her environmental activism is also visible in her work.