This qualitative study addresses the link between urban high school teachers' beliefs about their students' preparedness to achieve success in science and the teachers' reported curricular responses to those beliefs. Eight high school science teachers from schools representing a range of achievement levels were interviewed using semistructured, in-depth interview techniques. The findings suggest that teachers view science as a special subject that requires special qualities. Teachers saw their own students as largely lacking in those qualities needed for success in science and reported such modifications to the curriculum as "slowing down," deemphasizing some topics, and reducing the depth of coverage. (Contains 1 table.)