Research points to particular problems in the experiences of White teachers teaching students of color (Cochran-Smith et al., 2004). Despite good intentions, teaching students of diverse backgrounds and experiences can be challenging for teachers who are unfamiliar with their students' backgrounds and communities. The purpose of this paper is to describe the development of notions about "good urban teaching" for three women in a preservice teacher preparation program. Reporting on two years of data, we show how the three women negotiated their beliefs and identities in light of program demands and classroom realities. The lack of synchronicity within the women's experiences highlights that the traditional (white, female, middle class) students in preservice teacher education programs are not homogeneous. The significance of this difference is highlighted through the concept of heterogeneity. We define heterogeneity as the differences that exist among traditional students in preservice teacher preparation programs. Our research suggests that heterogeneity is complicit in the progress or lack of progress of preservice teachers developing professional identities.