Supplementary assessment particularly re-exam in the context of Ethiopian universities was introduced with the principle of improving academic achievement of failing students having scores near to passing marks. Besides, using more extended type of grading system having plus and minus signs that provide more broader and detailed view about students performance rather than using the traditional five point scale grading (A, B, C, D, and F) is prominent feature of higher institutions. Case study method was utilized to look the trends of re-exam in Haramaya University. The subjects of the study were instructors, students, registrar data managers and their respective heads. To incorporate instructors and students, purposive sampling technique was used. Available sampling technique was utilized to include registrar data managers and their respective heads. Questionnaire, semi structured interview and document review sheet were used to collect the necessary data. The finding of the study showed that, instructors were not sufficiently providing tutorials for their students before allowing them to sit for re-exam. Additionally; belittling, absence of fixed schedule (date and time) for re-exam, low instructors readiness & their bad perception towards re-exam were found to be the major challenges that affect the practices of re-exam. The relationship between study year level and the number of students who scored FX grade (r = -0.92, p < 0.05) was negative and significant. Keywords: FX grade; Re-exam; Supplementary assessment.