Due to the technological power and high status science is given in our society, educational reform efforts will continue to focus on science education. However, the purpose of science education for a multicultural society remains problematic. The implications of using social constructivism as a referent for science education is discussed, acknowledging that scientific knowledge, as all knowledge, is a cultural and sociohistorical construct. The position that social constructivism provides a theoretical base for creating multicultural science education is at odds with the view of science held by most science teachers. This case study follows two experienced middle school science teachers and shows how successful teachers change "good" teaching practices to make them "good" for all their students. One teacher participated in a four-year institute on multicultural science, while the other teacher revised his teaching practice primarily through his own trial and error experience. Participant observation methods were used to examine the salient features of transforming science education into multicultural science. A complex interplay between the nature of science and a pedagogical focus on the ability of the student versus content emerges as a precept differentiating the teacher's transformation of their science classroom and instruction. (Contains 33 references.) (Author)