Berganza studied at the Madrid Conservatory. In 1955 she made her debut in Madrid as a concert singer and toured Spain, Portugal, France, Italy, Austria, and Germany. She made her stage debut in 1957 at the Aix-en-Provence Festival in France as Dorabella in Mozart's Cosi fan tutte, and in the following year she appeared in Milan at La Scala in Rossini's Le Comte Ory, at the Glyndebourne Festival in East Sussex, Eng., as Cherubino in Mozart's Le nozze di Figaro, and in Dallas, Texas, as Isabella in Rossini's L'italiana in Algeri. In 1960 she sang her first Rosina in Rossini's Il barbiere di Siviglia at Covent Garden, London, and in 1967 she made her debut at the Metropolitan Opera in New York City in Le nozze di Figaro.

Berganza has appeared in many of the world's opera houses and made many concert tours accompanied by her husband, the pianist-composer Felix Lavilla.