This article reports a case study investigating the relationship between three teachers' stated beliefs about and practices of focus on form in intermediate level ESL communicative lessons. Focus on form was defined and studied in terms of incidental time-outs taken by students and teachers to deal with issues of linguistic form during communicative lessons. The teachers' statements of belief about focus on form were compared to their management of focus on form during lessons in which all the teachers used the same communicative task. Results showed some inconsistencies in the teachers' stated beliefs, in particular in relation to when it is legitimate to take time out from a communicative activity to focus on issues of form, and preferred error correction technique. While some statistically significant differences in the teachers' practices were reflected in differences in their stated beliefs, others were not. These results indicated a somewhat tenuous relationship between the teachers' practices and stated beliefs regarding focus on form. It is argued that future investigations of teachers' beliefs, especially of unplanned elements of teaching such as focus on form, need to be based on both stated beliefs and observed behaviours.