Students usually study the English language for seven years in Iranian schools. Although most of them master the related prescribed textbooks and pass their examinations with relatively good marks, very few of them leave the system with the ability to speak English effectively. It is the result of strong examination washback. This study was an attempt to investigate the nature and scope of the University Entrace Examination washback in English education in Iranian pre-university centers based upon Teachers' perceptions.This is the first empirical study of washback in Iran which has employed both quantitative (survey questionnaire) and qualitative (focus group interview) research methods. By combining qualitative and quantitative methods, this study provided solid research evidence of the washback impact of the UEE on various aspects of Iranian Teachers' curriculum planning and instruction.