Born in St. Petersburg, Russia, Katia Trebeleva studied playing the piano at the Music School. In 1992 she graduated from the St. Petersburg College as a chorus conductor. From 1993 to 1998 she studied singing at the St. Petersburg Conservatory and was immediately engaged by the National Opera of Estonia, where 23 years-old singer made her successful debut as Cio-Cio-San in "Madama Butterfly", where she returned next year as Giordetta in Puccini’s "Il Tabarro". In 1998 Ms. Trebeleva was invited by Wexford Opera Festival, where sang Micaela in "Carmen" and The Bride in "The Wedding" by Stravinsky. In 1999 she performed Adina in L’elisir d’amore with Vaasa-Opera in Finland and Sofia in Prokofiev’s "Semen Kotko" at the Mariinsky Opera (St. Petersburg). Since 1999 Ms. Trebeleva is a principal with the Moscow Helikon-Opera company, where she performed Tatiana in "Eugene Onegin", Maria in "Mazepa", Marpha in "The Zar’s Bride", Nedda in "I Pagliacci", Antonia in "Les Contes d’Hoffmann", Russalka in Dvorak’s "Russalka" and others. In 2001 she appeared as Lucrezia in Verdi’s "I due Foscari" with Mosсow New Opera. The same year Katia Trebeleva made her moving debut with Opera de Monte-Carlo in the titled role of Tchaikovsky’s "Iolanta" welcomed with italian and american mass-media.

She also performed Tatiana at the Festspielhaus in Salzburg, Vitellia in "La Clemenza di Tito" at the Merida Festival (Spain), Maria in "Mazepa" at the New Israeli Opera, Marpha in "The Zar’s bride" at the Massimo Bellini Theatre (Italy) and Blanche in Poulenc’s "Dialogues des Carmelites" at the Festival Al Bustan (Lebanon) with the Helikon-Opera tours. In 2006 she sang Diana in Martin y Soler’s "L’arbore di Diana" at the Hermitage Theatre at the Festival “Spanish Evenings in St. Petersburg”, the musical director and conductor of the production being Alexis Soriano.

Last autumn 2008 the singer gave her charming recital for Moscow public on the Helikon-Opera stage, presenting impressive masterpieces of chamber vocal music by world famous composers: Tchaikovsky, Rahmaninov, Gavrilin, Grig, List, R. Strauss, Poulenc. The same season 2009 Ms. Trebeleva started as Tsaritsa Alexandra Feodorovna in world premiere of opera "Rasputin" by the american composer Jay Reise, the staging by Dmitry Bertman. As well as made her first appearance as Rosalinde in J. Strauss’ "Die Fledermaus, Verdi Requiem in Voronezh and 4-th Symphony by Gustav Mahler.

Collaboration with following conductors: Gennadij Rozhdestvensky, Kirill Tikhonov, Vladimir Ponkin, David Lloyd-Jones, David Agler, Daniele Callegari, Marcello Rota, Paul Magi, etc.