This monograph addresses the issue of washback'. What is washback'? What does it look like in practice? It is asserted that tests influence students who prepare to take them, and teachers who try to help the students, thereby influence learning and teaching in schools. Washback' effect refers to these influences of the testing (Alderson and Wall, 1993). Although professionals have written about the concept, as yet little is known about how washback' actually functions, whether it really exists and (if it at all exists) what its nature looks like in the day-to-day school operation. This work examines the washback' effects of the Grade 10 EGSEC English Language Exams in selected schools in Ethiopia. An attempt is also made to determine the nature of the washback effect. The findings revealed that the exam has washback effect on the students' and the teachers' perception of the students' learning. And when seen from the point of view of coverage, ... and appropriateness, the exam is found to have negative washback' effect. Based on the findings, relevant conclusions were drawn and implications for future test design were discussed.