This study aimed to investigate the areas that constituted the professional practical knowledge of experienced English as a Foreign Language teachers in Egypt and how their knowledge informed their classroom practice. Quantitative and qualitative data were collected from 236 preparatory and secondary school teachers in 38 schools through questionnaires, semi-structured interviews and stimulated recall following classroom observation. Six areas of knowledge were revealed and rationalized from the participants' responses. In addition, the teachers made decisions while teaching informed by what they knew and viewed. The findings of the study call for a knowledge-based practical approach to teacher learning and professional development.