Curriculum reform has been reviewed as the preferred vehicle for Indonesian educational reform.Since 1975 the National curriculum has been reformed four times (Curriculum 1975, 1984,1994 and 2004. Each of these curricula aimed at being an improvement of the preceding one. However, despite the attempts made, the implemented curricula were still unable to fulfill the government intentions. This study, therefore, investigated educational practices in primary school science classrooms with large to small discrepancies observed between the intended and implemented instructional strategies. The observed discrepancies were explained by six factors, namely time constraints, non-alignment of examinations and the intended curriculum, lack of instructional support, lack of instructional materials and teacher professional development,teacher's belief and resistance to change. The findings can provide practitioners in the field with significant information for comprehending the present state of educational practices in urban and rural primary school science classrooms; the opportunities to question and rethink the challenges faced by teachers to implement a new curriculum in their classrooms.