Abstract: The revised 1990 mathematics syllabus for the New Mathematics Curriculum is being implemented progressively in Singapore schools since 1991. It is a transition period for teachers adapting to any new changes in the curriculum. The purpose of this study is to identify the stages of concern and the types of constraints faced by primary and secondary school teachers that are brought about by changes in the mathematics curriculum. The results show that most of the teachers were aware of the new curriculum and many were already teacher it, however, the initial stages of concern regarding needs for more knowledge and understanding of the rationale for new topics and personal needs like new skills to cope with these changes were fount to be most intense and urgent. As such, their open-ended statements of concerns reflected that they fely strongly the constraints of time which was related to the increase in load of the content, lack of knowledge on new topics and teaching skills to help their pupils especially those whom they believe were not ready due to slow cognitive and language development. The results of this survey have implications for improvement in training teachers for the new syllabus.