Borg (2003) defines “teacher cognition” as how teachers think, know, and believe. According to Borg, teacher cognition, classroom practices, learning experiences, teacher education, and contextual factors all relate to and influence each other. He also points out that researchers need to investigate the cognition of secondary school English teachers whose first language is not English, particularly those working with large classes of learners. Accordingly, in this study, I investigated how Japanese high school teachers perceive the use of Communicative Language Teaching (CLT) in their English classes. Since 1989, the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) has attempted to promote higher achievement in English communicative skills among secondary school students by urging teachers to use CLT. This focus on CLT in Japan contrasts sharply with the traditional and arguably still dominant yakudoku method, which involves decontextualized grammatical instruction and word-by-word translation of written English into Japanese. To achieve this communicative innovation, MEXT institututed a 5-year Action Plan in which intensive teacher training programs for 60,000 secondary school English teachers and the introduction of a listening component in the Center Test (a nationwide college entrance exam) were important features. To date, little research has been done on how high school teachers perceive and use CLT and how their cognition has been affected by its communicative orientation. To investigate teachers’ cognitive and practical adjustment to this landmark innovation, I conducted a survey of Japanese high school teachers’ cognition and practices regarding CLT. I posited three questions: What beliefs do Japanese high school teachers hold about CLT? How do they use CLT in their English classrooms? How do they perceive their teaching efficacy, their experiences in pre- and in-service training, their learning experiences, and contextual factors? Data were obtained through a questionnaire, based on previous studies of teacher cognition. The questionnaire was sent to randomly selected Japanese high schools in the fall of 2006, and 139 teachers responded. The data were analyzed using descriptive statistics, t-tests, and a one-way analysis of variance (ANOVA). As regards the first research question, the descriptive statistics showed that the respondents held positive beliefs about CLT. At the same time, they believed that rote memorization is important. In addition, more than half of the respondents said that they wanted to make their lessons more communicative, and the largest number answered that smaller class size should be maintained in order to use CLT effectively. With respect to the second research question, the respondents did not frequently use communicative activities. There seemed to be a gap between their reported beliefs and practices. Concerning the third research question, results indicated that (a) the respondents had less confidence in their ability to implement CLT than in their English skills and grammatical knowledge, (b) the respondents had fewer opportunities in pre-service training courses than in in-service training programs to receive practical training in CLT, (c) they perceived that the classroom conditions were not optimal for the use of CLT, (d) MEXT innovations had not strongly influenced their classroom practices, and (e) they had had few chances to experience communicative activities in English class when they themselves were in high school. It appears that these factors had a negative influence on the respondents’ use of CLT. In summary, the respondents held positive beliefs about CLT, but there was a gap between their reported beliefs and practices. In order to make Japanese high school English lessons more communicative, contextual factors and teacher training programs should be re-examined and context-appropriate communicative methodologies should be developed by teachers themselves. 文部科学省は、1980年年代後半から英語によるコミュニケーション能力を高めようと、高校の授業でのコミュニカティブ・アプローチ(CLT)の採用を促してきた。また、2003年から5年間にわたり「『英語が使える日本人』の育成のための行動計画」を実施し、その方針の具体的な実現を図った。本研究では、無作為抽出した高校に質問票を送付し、日本人高校教師がCLTをどのように考え実践しているか、また、教師としての能力、教職課程、教員研修、学習経験、教育環境などをどのようにとらえているかについて、2006年秋に調査した。その結果、回答者139名の約60%は、CLTの理念(「言葉は使うことで効果的に習得」「コミュニケーション能力の育成が大切」「間違いは学習の一環」など)に賛成(或いは強く賛成)しているが、コミュニケーション活動を普段の授業で使っている回答者は全体の30%に満たないことがわかった。結果を踏まえてどのような要因がCLTの実践に影響しているかを考察する。