Nicola Ghiuselev had the rich, full timbre and seemingly effortless low notes that characterize the classic Slavic bass voice. It also had a strong enough top that he could perform bass-baritone roles such as the four villains in Offenbach's The Tales of Hoffmann, and even Mozart's Don Giovanni. He first studied both painting and music at the State Conservatory in Sofia, but after deciding he had better career prospects as a singer, he concentrated on that. He made his opera debut at the Bulgarian National Opera in 1960 as Timur in Puccini's Turandot, and soon rose to starring roles with that company. In 1965, he made his Metropolitan Opera debut as Ramfis in Verdi's Aida during a company tour, followed two years later by his Covent Garden debut as Pagano in Verdi's I Lombardi.