Within the context of an ongoing reform of the curriculum for English as a foreign language (EFL) in China, we present the implicit association test (IAT) as a new way to measure Chinese EFL teachers' implicit attitudes to a communicative language teaching (CLT) curriculum and to compare their attitudes to traditional language teaching (TLT) approaches. Our study is framed within the theory of teacher cognition -- what teachers know, think, and believe as active decision makers (Borg, 2003) -- and we propose the IAT as a new instrument for education researchers and policy makers. The IAT was used to discover the implicit attitudes of 24 Chinese EFL teachers, all graduates of the same teacher training institution in China, currently teaching at middle, high school, or college level in the same Chinese city. Results showed different degrees of implicit preference for CLT over TLT of the 24 teacher participants. We also found differences between implicit attitudes and explicit attitudes expressed by three teachers in interviews and we attributed those differences to the personal, institutional, and social contexts in which they were teaching. Results revealed that what teachers say is not necessarily what they think. By using the IAT, we have been able to measure implicit attitudes in a way that has never been done in teacher education study. We argue that such measures of teacher cognition are important for successfully implementing curriculum reform.