This study explores the practices of three beginning secondary science teachers. The teachers were in their first year, worked with primarily Hispanic students in rural and urban schools, held undergraduate degrees in science, participated in postbaccalaureate certification programs of varying lengths, and had different cultural backgrounds from the majority of their students. Their beliefs, practices and experiences were documented over the course of a year using the following data sources, semistructured interviews, participant observations, electronic communications, and classroom documents. From the data, individual teacher cases were constructed and then the cases were compared to each other. Conclusions included that the intentions of beginning teachers did not always translate into reality and that enthusiasm for working in diverse environments was not enough for them to enact reform-based practices. The beginning teachers were negotiating a wide range of new experiences, they were just developing their ability to work in these school settings, and they often made their environment less ambiguous by using practices familiar to them. This study suggests that beginning teachers who are working with populations different from their own background require preservice and induction programs that support crucial practices and that those who hire beginning teachers need to take initial teaching assignments into careful consideration.