This study examined how student teachers spent their time during student teaching and the structural conditions in the classroom that may have influenced these activities. Specifically, the nature of student teachers' activities was investigated relative to time spent in subject areas, grouping arrangements, and observing and teaching. Data collected from 10 student teachers, graduate students enrolled in a one-year post-baccalaureate teacher education multiple subjects credential program at an urban university in Southern California, indicated that classroom activities among student teachers varied considerably, even within a single teacher education program. Differences were found among student teachers in time spent in the transition from observing to teaching; time spent in individual, small group, and whole group instruction; and time spent in curricular areas. The transition of student teachers from observing to teaching, however, was similar in that teaching increased and observing decreased over time. (Author/CB)