Rusty Warren, a classically trained pianist who became a wildly popular comedian in the 1960s, known for her earthy jokes about sex and relationships, and was sometimes called a godmother of the sexual revolution, died May 25 at a caregiver’s home in Orange County, Calif. She was 91.

She had chronic obstructive pulmonary disease and other ailments, said her partner, Liz Rizzo.

Ms. Warren’s bawdy comedy was tame by the profanity-laced standards of today, but it was considered so outrageous for its time — especially coming from a woman — that she was effectively banned from television and radio.

As a result, she never achieved the mainstream fame that, say, Phyllis Diller and Joan Rivers did, but she had a loyal following of fans who bought her record albums by the millions and made her one of the highest-paid nightclub comedians of her time.

Long before it became a common subject for comedians, male and female alike, Ms. Warren was joking about the joys and headaches of sex. Between 1959 and 1977, she recorded 15 comedy albums, seven of which became gold records, with sales of more than 500,000 each.

Her 1960 album, “Knockers Up!” — the title track is a march-like ditty that can be taken as a pre-women’s movement affirmation of female pride — was on Billboard’s charts for more than three years and sold an estimated 4 million copies. Because of the album’s subject matter, they were called “party records” and were considered too vulgar to be played on the radio.

“In short, she is just another dirty comedian who deprives sex of all its grace and sophistication, while she claims to be helping inhibited females to enjoy themselves,” an anonymous critic wrote in a scathing 1963 Time magazine article.

“Many women regularly bring their husbands to hear her, blue-suit and brown-shoe types that have never seen a nightclub. Like Rusty, they all seem at home in a barnyard.”

At first, Ms. Warren was stung by the criticism, but it turned out to be good publicity for her act. Billed as “The Knockers Up Girl,” she had sold-out engagements at nightclubs around the country. At the height of her fame in the 1960s, she was making $30,000 a week in Las Vegas.

“She was one of the first women to speak about sex and was really a comedian for women,” Andrew Buss, a comedy archivist and editor of the Laugh Button website, said in an interview. “People like her made it possible for women today to go onstage and talk about sex. They didn’t call her the mother of the sexual revolution for nothing.”

Ms. Warren wore colorful gowns as she performed catchy comic songs at the piano while bantering with audiences in her late-night cabaret act. Unlike other “blue” female comedians of the time, such as Belle Barth and Pearl Williams, Ms. Warren did not use four-letter obscenities, preferring innuendo and the power of suggestion.

Nonetheless, she was considered daringly original for her frank and racy jokes about breasts — for which she used a variety of terms — the fragile male ego and the hidden desires (and fears) of women.

“I talked about the sexual attitudes of men and women,” Ms. Warren told the Boston Herald in 1999. “None of it was a secret, it just wasn’t talked about publicly until I came along. That’s where the shock value came from.”

Much of her act was ad-libbed, drawn from observations of her audience.

“Come right in, good evening how do you do?” she might say. “Hmm. One gentleman and three ladies. There is a man that is contemplating a busy weekend.”

Or she might say to a woman: “I notice, young lady, that you have a V-neck dress on, slit down to your navel with a stunning ruby in your navel. . . . That ‘V’ on the dress, does that V stand for virgin? Oh, it does?” After pausing to chuckle, she added, “Must be an old dress.”

Ms. Warren’s most devoted fans were women, she said, because they saw their lives reflected in her humor. She drew her jokes from the mores of the 1950s, when women seldom worked outside the home and were expected to marry and be attentive to the needs of their husbands.

She got her ideas from “sitting at a piano bar at 2 in the morning and listening to some guy’s wife talk,” she told the Chicago Sun-Times in 1975. “My routines were coming from the people. Out of a wife dreading her husband coming home from the office with one thing in mind.”

Ilene Goldman was born March 20, 1930, in New York. She was adopted as an infant and grew up in Milton, Mass. Her father was a railroad engineer, her mother a homemaker.

She began to study piano at age 6 and graduated from the New England Conservatory of Music in 1952. She briefly taught at the conservatory and once performed, as part of a group of 21 pianists, with Arthur Fiedler and the Boston Pops.

During the summers, she was a pianist in resort hotels and began to joke with audience members as she played. She developed an act modeled on that of Sophie Tucker, who encouraged Ms. Warren in the 1950s, telling her to write her own material and to “be honest in everything you say, or they’ll see right through you.”

By 1954, Rusty (from her reddish hair) Warren (from a street in her hometown) was appearing around the country, “singing saucy and naughty songs . . . the way you like ’em,” as one promotional ad had it.

“Rusty Warren is really a part I’m playing,” she said in 1961. “That’s the only acting ambition I have — to play Rusty Warren well.”

Her recordings, which included “Songs for Sinners,” “Rusty Bounces Back,” “Rusty in Orbit” and “Sin-Sational,” sometimes outsold the albums of male comics such as Bob Newhart, Shelley Berman and Jonathan Winters.

Ms. Warren’s career slowed in the 1970s, and she had largely retired by the 1990s. She lived in Arizona for many years and later had a home in Hawaii. She had wide-ranging business interests, including real estate, apartment buildings, publishing and manufacturing.

Survivors include her partner of 35 years, Liz Rizzo of Kailua, Hawaii.

“We were always trying to prove ourselves. That was what my humor was about,” Ms. Warren told the Sun-Times in 1975. “I built those sex stories . . . out of what I thought most women feel but didn’t have guts enough to say.”