This study aims to investigate the beliefs and real practices of four English writing teachers in relation to their written corrective feedback (WCF) and verify whether these beliefs and practices are compatible or not in an ESP context in the preparatory year in Saudi Arabia. The participants in his study were four teachers and fortystudents at the preparatory year in the English Language Center at Umm Al-Qura University. Data were collected via three qualitative instruments, namely classroom observations, semi-structured interviews, and document analysis of 40 student essays. Findings showed that teachers' practices match their beliefs in different areas related to the significance and purpose of their own comments as a primary source of WCF as well as providing comprehensive (unfocused) and varying feedback based on the kind of error and the students' ability levels. Conversely, teachers' practices do not accord with their beliefs with respect to providing direct/indirect, positive/negative feedback. Several contextual factors that influence teachers' behaviors and decisions and shape their WCF practices are identified. The four teachers interviewed have personal values, individual preferences, and behavioral convictions that do not align with the school's policies and regulations. Further, the study concludes that they do not have the essential educational background and work experience to make them professional ESP writing teachers, did not receive any specific on-the-job training related to ESP writing instruction, have a heavy teaching workload, and deal with too many students most of whom are weak and unmotivated. The study recommends that work conditions for teachers should be improved. More importantly, teachers selected to teach ESP writing should be provided with adequate periodic training to help them acquire the necessary pedagogical knowledge and qualify them to build positive beliefs to provide effective feedback.