This paper reports on detailed case studies into emerging assessment practices in technology in two New Zealand primary schools (Years 1–6) with nine teachers. This research is part of the two year Research in Assessment of Primary Technology (RAPT) project and formed the basis for the one year New Zealand Ministry of Education funded Learning in Technology Education (Assessment) project. Emerging classroom assessment practices in technology, a new subject area in the national curriculum, are discussed. It was found that the existing subcultures in schools, teachers' subject expertise and the school wide policies impacted on the teachers' assessment practices. Assessment was often seen in terms of social and managerial aspects such as team work, turn taking and information skills, rather than procedural and conceptual aspects. Therefore teachers' formative interactions with students distorted the learning away from procedural and conceptual aspects of the subject, and the learning and the formative assessment interactions focused on generic skills rather than student technological understanding. The importance of developing teacher expertise in three dimensions of knowledge about the subject, knowledge in the subject and general pedagogical knowledge is highlighted. Thus the findings from this research have implications for thinking about teaching, learning and assessment in technology.