This article reports a 2-year case study (2003-2005) on teachers' instructional practices, and the impact of teacher understandings and training upon the teachers' implementation of the Communicative Oriented Curriculum (COC) initiative in the context of a major curriculum innovation in teaching English to young learners in Turkish state schools. Using multidimensional qualitative research procedures, comprising classroom observations, teacher interviews and lesson transcripts, a picture is developed of how 32 teachers implemented COC. Results showed that teachers' instructional practices ranged along the transmission and interpretation teaching continuum, and teachers' understandings and their prior training had an impact on the extent of their implementation of the curriculum initiative. The study highlights the need to provide "continuous" teacher training and teacher development opportunities, "particularly during the critical first few years of the innovation process" to promote the implementation of curriculum innovation in Turkish primary education. (Contains 2 figures and 4 tables.)