Toimii (Finnish for "It works") is a new music ensemble founded in 1982 by Magnus Lindberg, Esa-Pekka Salonen, Otto Romanowski, Anssi Karttunen, Kari Kriikku and Juhani Liimatainen.

Toimii was formed to be a laboratory for composers, instrumentalists and other artists to discover new ways of imagining and creating music. The idea of Toimii came while Magnus Lindberg, Otto Romanowski, and Esa-Pekka Salonen were preparing a concert performance of Karlheinz Stockhausen's Plus-Minus. One important influence for Toimii was Vinko Globokar and the improvisation group New Phonic Art. The first concert of Toimii! was at the Jyväskylä Summer Festival in 1982. Lindberg's composed for the occasion Action-Situation-Signification which was coupled with Correspondences by Vinko Globokar. The name of the ensemble originally included an exclamation mark, it was dropped when another ensemble in Finland adopted it.

Apart from performing a few existing works and creating collective pieces, Toimii encouraged poets, painters, dramaturgists and actors to compose for their concerts. Toimii believed that all artists create through a similar process and can thus communicate through each others work.

Each rehearsal period started with no determined program in mind, the rehearsals consisted of combining existing pieces with improvising, last minute composing and arranging. All of the members had an equal input into every detail of each concert. Toimii believed that an idea is such a rare natural resource that if anyone ever had one, it was always followed.

Magnus Lindberg's 1985 cult piece Kraft is a concerto for Toimii and a Symphony Orchestra, the ensemble toured around the world performing the piece 14 times and recorded it twice.

Toimii performed widely in Europe and in the US and visited many festivals in locations as far apart as Uusikaupunki, Tromsø and Ojai. While its members became increasingly involved in their own lives, they still continued meeting once or twice a year through the 1990s for a week of intensive rehearsing.

Toimii also performed very successful children's concerts; at the Suvisoitto-festival in Finland, at the Ojai Music Festival and at the Queen Elisabeth Hall in London,

The last appearances of the complete Toimii ensemble were in December 2001 at the Related Rocks Festival in London and in 2003 in Helsinki where they also made their second recording of Lindberg's Kraft.

You can hear Toimii every time any of its members is on stage. Toimii never leaves its members. Toimii is alive.