The article examines the origins and purposes of assessment for learning (AfL) within the National Curriculum Assessment context in England. As a part of the Primary Strategy, AfL became part of the government's drive to improve standards through measuring school outcomes. The authors describe their investigation into teachers' understandings of AfL, how AfL has influenced teaching, learning and assessment in the intervening six years and whether it has established a presence as part of teaching pedagogy. (Contains 5 figures.)