This article presents the major findings of a small-scale study of recent changes in the elementary school curriculum in Portugal and their implications for teachers' sense of professionalism. Data were gathered through semi-structured interviews and questionnaires in a suburban elementary school. Findings suggest the emergence of contradictory trends in teacher professionalism: on the one hand, teachers acknowledge the flexibility and the local logic in the management of school curriculum in which they play a key role; on the other, they highlight issues of bureaucracy and 'imposed collaboration', along with the lack of support and guidance to perform their new roles at school. Challenge, ambiguity and tension are key words in defining Portuguese teachers' sense of professionalism in times of change.