Katia and Marielle are a sharply contrasted, yet highly communicative piano team. While their joint reputation was won initially through the performance of unusual repertoire, they have not neglected traditional works for two pianos.

The sisters received initial instruction from their Italian mother, an accomplished piano teacher, who began lessons when her daughters were three and five years of age. Madame Labèque had been born in Tuscany, in Torre del Lago, where Puccini's estate was located. The girls' father was a doctor from Landes. Following the preparation provided by their mother, the sisters entered the Paris Conservatoire where both of them took First Prizes. Upon graduation in their mid-teens, the two undertook performance of contemporary music, works by Berio, Boulez, Ligeti, and Messiaen, much to the surprise (if not the consternation) of those who had previously guided their careers. Indeed, during their first decade or so of public performance, this was the music for which they became best known. Each has commented that older audiences came to their concerts hoping to hear Mozart or Schubert and instead were treated to music that struck them with shocking effect. While a certain notoriety came with this performance repertoire, true celebrity arrived when their two-piano recording of Gershwin's Rhapsody in Blue sold over a half million copies in 1981.

As their reputation as a duo-piano team grew, the sisters enjoyed collaborations with many of the world's leading conductors, among them Riccardo Chailly, James Conlon, Sir Colin Davis, Charles Dutoit, Jesús López-Cobos, Seiji Ozawa, Sir Simon Rattle, Esa-Pekka Salonen, the late Giuseppe Sinopoli, Leonard Slatkin, and Michael Tilson Thomas. They have performed with most of the world's most prestigious orchestras in Amsterdam, Berlin, Boston, Chicago, Cleveland, Dresden, Leipzig, London, Los Angeles, Milan, New York, Philadelphia, and Vienna.

As recitalists, the Labèques have appeared at most of the world's most important music festivals.

The Labèques' personal attractiveness hastened their involvement with television production and they can boast of numerous appearances on broadcasts originating from Great Britain, Germany, Austria, Holland, Japan, and the United States. Their participation in the Washington D.C., gala, Piano Grand! in 2000 was viewed throughout America and in many other parts of the world. The Labèques have recorded extensively for EMI, Philips, and Sony, both duo recitals and concertos, the latter with several of the world's great orchestras. Their jazz-flavored recording, Love of Colours, has also been well-received. Katia has recorded several straight jazz albums, three of them with guitarist John McLaughlin.

The sisters moved from their London residence in 1993 and now live in a Tuscan palazzo (formerly owned by the Medici family) in which several pianos are housed. For a Bach Celebration with Musica Antiqua Köln in 2000 and subsequent appearances with Il Giardino Armonico, the Labèques commissioned two Silbermann instruments of mid-18th century design on which to perform music of that period.