This article examines Joan La Barbara's role in New York's Downtown scene, where her career was nurtured. By ‘La Barbara's Downtown’ I mean her perspective on Downtown as reflected in where she performed, who she collaborated with and what she wrote. Beginning with her involvement in the Steve Reich and Philip Glass ensembles in the early 1970s, I follow her through explorations in improvisation with Frederick Rzewski, Garrett List and Charlie Morrow. At the centre is La Barbara's development as an experimentalist composer in various Downtown venues, reinforced by her important collaborations with Alvin Lucier and John Cage. She wrote about the Downtown scene in the SoHo Weekly News in the mid-1970s and after leaving New York continued to write about it in Musical America until the mid-1980s. In all these contexts, I explore the different elements of her experimentalism, which is the overriding thematic of her aesthetic.