Maria Kliegel appears regularly as a guest soloist with leading orchestras at major concert venues all over the world. She has an exceptionally wide repertoire in her command: from the great masterpieces of the past to outstanding compositions by contemporary composers. Her versatility and her interest to explore new repertoire has repeatedly stimulated contemporary composers to write music for her. For example, she initiated the work Hommage a Nelson by Wilhelm Kaiser-Lindermann, dedicated to Nelson Mandela. As a result of the composition's success Maria Kliegel was invited by the former South African President to give a private recital. Maria Kliegel also takes care of the next generation of cellists. She has been teaching master classes at the Cologne Music Academy since 1986.
She plays the legendary violoncello "ex Gendron" made by Stradivarius in 1693. For more than 30 years, it was owned by Maurice Gendron and was eventually put at her disposal by the Stiftung fur Kunst und Kultur in NRW (Foundation for the Arts and Culture in North Rhine Westphalia). In November 1998, she has been appointed member of the board of the Deutscher Musikrat. In 1999, she was awarded the Order of Merit of the Federal State of North-Rhine Westphalia by Minister-President Wolfgang Clement.