NEW YORK - Singer Lili Chookasian, an American who in the 1960s and afterward was among the most prominent contraltos in the world, died Tuesday at her home in Branford, Conn. She was 90.

Her family confirmed the death.

Ms. Chookasian was a principal singer with the Metropolitan Opera for a quarter-century, appearing there 290 times from 1962 to 1986. She also sang in recital and was a soloist with many of the world’s leading orchestras.

Critics and operagoers hailed Ms. Chookasian as a “real contralto.’’ Where many contraltos are endowed with the lightish, dusky equivalent of a viola, her voice - immense, deep, velvety, and burnished - put a cello at her command. She was also praised for her sensitive musicianship, powerful dramatic characterizations, and impeccable diction. (She had grown up speaking Armenian.)

Ms. Chookasian made her Met debut in 1962, at 40, in the role of La Cieca in “La Gioconda,’’ by Ponchielli, with Franco Corelli, Robert Merrill, and Zinka Milanov.

She was perhaps most closely associated with the work of Gian Carlo Menotti. At the Met, she sang the Maharanee in the US premiere of his opera “The Last Savage.’’ On loan from the company, she made her New York City Opera debut in 1963 as Madame Flora, the title character of his two-act opera “The Medium.’’

Her other Met roles included Amneris in Verdi’s “Aida,’’ Erda in Wagner’s “Rheingold’’ and “Siegfried,’’ and Mamma Lucia in Mascagni’s “Cavalleria Rusticana.’’

The daughter of Armenian immigrants, Lillian Phoebe Chookasian was born in Chicago; her father was a machinist and toolmaker. A gifted singer from girlhood on, she made her professional debut in the 1940s as a soloist on the radio show “Hymns of All Churches,’’ broadcast nationally on the Columbia network.