In 1990, a year before beginning her master's degree in choral conducting at the University of Illinois at Urbana-Champaign, Kristina Boerger decided to form what she advertised as a lesbian/feminist chorus called Amasong. The group's name was a play on the words amazon and song. Boerger said, "The word amazon conjures up images of strong women who make their own decisions. It was a way of coding our group in a certain way."

Boerger posted flyers around town about her new choral group, Amasong. Many local women responded to the flyers. A roomful of women showed up at the first choir rehearsal, consisting mainly of lesbians, feminist housewives, and students. The decision to label Amasong as lesbian/feminist was important. In the PBS documentary The Amasong Chorus: Singing Out, produced by Jay Rosenstein, Boerger explained, "There's lesbian-feminism with a hyphen, which refers to women who are lesbian and feminist. But if you put a diagonal slash between, then it means either/or. And that's very important. Whenever I tell people on the phone who we are, I make sure they get the punctuation correct. It doesn't mean you have to be both to get in the choir. It means you've got to be one or the other." The choir's first members were diverse in interest, age, and experience, and this has continued to the present version of the chorus.