Ileana Cotrubas was one of the most expressive singing actresses of her era. She specialized in operatic roles calling for a degree of pathos, such as Violetta, Ilia in Idomeneo, Mimì, Gilda, and Mélisande, but she also had a gift for comedy that was well expressed in roles such as Susanna in Le nozze di Figaro, Norina in Don Pasquale, or Adina in L'elisir d'Amore. She held strong beliefs about staging, and more than once caused controversy by walking out of a production which she believed was inappropriate for the opera in question. Her voice and vocal production, too, were somewhat controversial: while her admirers praised it for the undefinable quality of "morbidezza" and for an almost childlike tone of vulnerability, others found it saccharine. Some listeners, too, found her audible breathing to be distracting. While the majority of her career was in opera, she also sang sacred music, particularly Mozart, and gave the occasional lieder recital.
Her family was a musical one, and she began her own singing career when she joined the Children's Chorus of Radio Romania at the age of nine, and by the age of 11 she had graduated to solo parts. Her family moved to Bucharest in 1952, and she enrolled at the Scoala Speciala de Musica, a musical training academy for children. In 1958, she continued her studies at the Ciprian Porumbescu Conservatory. In 1964, she made her operatic debut at the Bucharest Opera as Yniold in Pelléas et Mélisande, a role sung either by a boy soprano or an adult lyric soprano, and continued there, singing lyric and coloratura roles such as Gilda in Rigoletto, Oscar in Un ballo in maschera, Blonde in The Abduction from the Seraglio, and even Siebel in Faust. In 1965, she won the first prize at the International Singing Competition in Hertogenbosch, Holland, followed by similar success at the 1966 Radio Competition in Munich. She made her debut in England at the Glyndebourne Festival in 1969, singing Mélisande, and her Covent Garden debut in 1970 as Tatyana in Eugene Onegin. Throughout her career, she maintained close ties with both the Festival and Covent Garden, and maintained a home in Kent, England. In 1970, she signed a non-exclusive three-year contract with the Vienna State Opera, singing there and also making her U.S. debut at the Lyric Opera of Chicago as Mimì. In 1975, she made her La Scala debut on extremely brief notice, replacing an ill Mirella Freni as Mimì (a role that has been a calling card for both sopranos), and in 1977, made her Met debut in the same role. In 1981, she was named a Kammersangerin by the Austrian government. In 1989, she announced her retirement, and focused her energies on teaching. Her best-known pupil is Angela Gheorghiu, her Romanian compatriot.
In comic opera, her Adina in L'elisir d'Amore is excellent (Sony M2K 79210), and she also made a lovely and touching Violetta in La traviata (Deutsche Grammophon 35417). She also made a fine recital CD on Sony (SMK 60783), which features her in both her core repertoire and some roles she never sang on stage.