This study aimed at investigating grade four students learning at Jimma town, Ethiopia. A cross sectional survey method was employed. Students, teachers and principals were participants of the study. Standardized tests, questionnaire, interview and observation were the instruments used to collect authentic information from the research participants. The collected data were analyzed quantitatively using various statistical techniques and qualitatively categorizing it in to different themes to substantiate the numerical data. The result indicated that students' learning achievement was inadequate in two key subjects namely English and Mathematics which are the core subjects in all education levels of the country. Moreover, there was immense gap among schools and across subjects in students' performance. The major reasons identified were students' background (family socioeconomic status and educational level and mother tongue), students' interest and attitudes towards key subjects (English, Mathematics, Environmental Science and Mother tongue), availability of learning resources and support from school and the families/guardian. From the factors, the most prominent ones are issues related with their home related problems and utilization of the available resources. Thus, researchers recommended that relentless effort should be exerted by all stakeholders to bring students to the level expected of them as stated in the curricula.Key words: Assessment, learning assessment, key subjects. INTRODUCTION Background of the studyThe main purpose of education, especially at primary level, is to enhance economic and social development of a country by creating learning opportunities at individual, community, and national levels, and to expand literacy and give basis for further training and self-education (MoE, 1994). To attain such major aims, various countries have been designing and implementing different strategies for expanding access and improving quality of schooling.Cognizant of this, Ethiopia also introduced free primary -I, 1996) within the framework of education and training policy as part of a twenty-year education sector indicative plan. The main thrust of ESDP-II (2000) is to improve education quality, relevance, equity, and efficiency and to expand access with special emphasis on primary education in rural and underserved areas, as well as the promotion of education for girls (MoE, 2006). Accordingly, under ESDP III (2005), Ethiopia made significant progress in education. Access at all levels of the education system increased at a rapid rate in line with a sharp increase in the number of teachers, schools and institutions. There were important improvements in the availability of trained teachers and some other inputs which are indispensable for a high quality education system. This has led to rapid increase in the net enrolment rate, which currently stands at around 83% of primary school aged children.The achievements under ESDP III are fundamental to allow Ethiopia to progress towards becoming a middleincome...