The purpose of this study is to survey Japanese senior high school English teachers' awareness of their communication strategy (CS) use in English and of their teaching of CS use to their students in class, and also to discuss the interrelationships of the strategies. Using a 5-point Likert scale, the questionnaire items were made based on the CS list of Celce-Murcia, Dörnyei and Thurrell (1995). Each questionnaire item has two component factors: (1) how often the respondents use a particular CS as language users; and (2) whether they teach it to their students explicitly in class. The survey was conducted in February and March of 2007, and 120 high school teachers participated in it. Some of the major findings are: (1) the above two component factors are closely related to each other; (2) in CS use and instruction, RESPONSE and REQUEST are the two most used categories and they correlate strongly with many others; and (3) AVOID is the least-used strategy and its perceived value varies greatly from teacher to teacher. Finally, two pedagogical suggestions are made to aid the development of strategic competence in Japanese high school students and to become more active participants in communication.