After first experiences at the theatres Bremen, Schwerin, Flensburg and Bremerhaven, Cornelia Ptassek was engaged at the Nationaltheater Mannheim, where from 2005-2016 she was a member of the ensemble.

During this time she was able to expand her repertoire extensively and is today just as at home in lyrical roles as in youthful drama. In addition, Cornelia Ptassek can refer to broad experience in the field of musical rediscoveries and new music. 

In recent seasons she sang the title role in Cherubini's Medée, Mozart's Elettra in Idomeneo, Strauss' Salome at the Nationaltheater Mannheim and was able to celebrate national success as Grete in Schreker's Der Ferne Klang and as Gluck's Alceste.

She has been working as a freelancer since the 2016/17 season. Guest performances have taken her to the theaters in St.Gallen, Würzburg and Trier, among others. At the Theater Lübeck she appeared in 2022 after several performances as Ariadne, a new production Der Ferne Klang as Grete, a concert production as Heliane in Das Wunder der Heliane by Schreker and the Four Last Songs by Strauss, in 2021/22 in a gala, which instead of the planned Medea by Cherubini took place to hear.  
At the Chemnitz Theater she could have been seen in 2022 in Elisabeth Stöppler's highly acclaimed Götterdämmerung production as the 3rd Norn and as Gutrune and in Lohengrin there as Elsa. This was canceled due to the corona virus.

In 2023 she sings there Elsa in Lohengrin and gives her debut as Marie in Wozzeck.

She also gave her first master class there in the summer of 2021. She acted as a consultant for an audition at the Musikhochschule in Munich and taught at the Choratelier Siena in the summer of 2022.

The broad repertoire of the diverse and versatile artist includes:  
Donna Anna in Don Giovanni, Fiordiligi in Cosí fan tutte, Contessa in Le nozze di Figaro, Elettra in Idomeneo, Aspasia in Mitridate and Pamina in The Magic Flute, 
Wagner's Elsa in Lohengrin and Eva in Die Meistersinger, 
Strauss' Salome, the Marschallin in Rosenkavalier, Ariadne in Ariadne auf Naxos and Chrysothemis in Elektra, 
Verdi's La Traviata and Puccini's Liu in Turandot.

 

In addition to her permanent engagement at the Nationaltheater Mannheim, she was heard in guest performances at home and abroad, for example at the Stuttgart State Opera under Sylvain Cambreling in the new production of Boesmans' Der Reigen as a singer.
In recent years, Cornelia Ptassek has appeared at the Freiburg Theater (as Strauss' Ariadne), at the Mainz Theater (as Cherubini's Medée), at the Teatro de la Maestranza in Seville (as Wagner's Helmwige in Die Walküre im Fura-dels-Baus-Ring ), at the Theater des Champs Elysées in Paris with Kurt Masur (as Marschallin in Strauss' Rosenkavalier) and with the Stuttgart Philharmonic under the baton of Gabriel Feltz in Beethoven's 9th symphony. 
Engagements have taken her to the Gärtnerplatztheater in Munich as Mozart's Pamina and Verdi's Violetta, to the Stuttgart State Theater as Strauss' Ariadne and Cherubini's Medea in a Konwitschny production, to the Mainz Theater as Wagner's Eva in Die Meistersinger, to the Basel Theater as Wagner's Elsa in Lohengrin and at the Lithuanian National Theater in Vilnius as Elettra in Idomeneo.
At the Gran Teatre del Liceu in Barcelona she was the cover for Véronique Gens as Wagner's Eva,
Guest engagements led her to the Festival du radio France de Montpellier and the Schwetzingen Festival (Le Grenzi's Il Giustino under Thomas Hengelbrock).