Martin Tzonev has performed leading bass parts including Colline in La Bohème (Vienna, Volksoper), Don Magnifico in La Cenerentola (Regensburg and Bonn), Paolo Albiani in  Simone Boccanegra (Mannheim and Bonn), Litore/Console in L'Incoronazione di Poppea (Amsterdam, De Nederlandse opera), both Leporello (Lübeck and Bonn) and the title role in Don Giovanni (Telón del Teatro Segura, Lima), Don Basilio in Il Barbiere di Siviglia, Banco in Macbeth, Mephistophélès in Faust, Padre Guardiano in La Forza del destino, Four Villains in Le Contes d'Hoffmann, Gobriaz in Belsazar, and Zebul in Jephta (all in Bonn).

Martin Tzonev performed Colline in La Bohème, Figaro in Le Nozze di Figaro, Mephistophélès in Faust , Surin in Pique Dame, and Selim in Il Turco in Italia, all in Bonn, where he is fixed engaged at present.

More recently he has performed the title role in Don Giovanni (Gijon, Spain) and Eurito in Pizzetti's Fedra (Festival Radio France), Ramfis in Aïda (Montpellier and Paris, Salle Pleyel), Mephistophélès in Faust (Montpellier), Astolfo in Vivaldi's Orlando Furioso (Bonn).

Upcoming engagements include Reimar in Tannhäuser, Varo in Händel's Ezio, Tchelio in Liebe zu drei Orangen, Colline in La Bohème (all in Bonn), and Theaterdirektor / Bankier in Lulu (debut at Salzburger Festspiele).