The objective of this study was to examine the practices and challenges of the implementation of continuous assessment in primary school cluster centers of Assosa Wereda. A descriptive survey design and both quantitative and qualitative methods were employed. The sampling techniques used included simple random sampling method, and purposive using Critical Case Sampling. 300 sample respondents were involved from primary school cluster centers as well as woreda education offices. The data were collected using questionnaires, focus group discussions, structured interviews, classroom observations and document analysis. The quantitative data were analyzed using descriptive statistics such as percentage, frequency, and mean values. The qualitative data were analyzed thematically using a case by case and cross case analysis. Finally, the study came up with the following findings. The status of the implementation practices of continuous assessment is still continued traditional, unsatisfactory and poor. It has deficiency and it is at a low level of implementation in primary school cluster centers of Assosa Wereda. The challenges teachers & students encountered during the implementation practices of continuous assessment were overpopulation, teachers lack of competencies and skills to carry out classroom assessment, lack of motivation, focus on the cognitive level and emphasis to the knowledge domain ignoring the affective and psychomotor domains, over concentration in written test, inadequate monitoring and support to the teachers and students absenteeism are the other challenges. The education sector professionals at all level should accept that the assessment at classroom level is at low level of performance and it is their faliuarity. So, they need to prepare guidelines and documents on continuous assessment at the beginning of each academic year to fill the gap, on record keeping avoiding distribution of simple and inappropriate assessment format. To improve the contribution of continuous assessment to the promotion it requires setting the average cutting score at the beginning academic year even during registration that make all concerned bodies to plan, strive and do their best in transition from the old/traditional continuous assessment practices/customs to the new contemporary continuous assessment. Key words: Assessment, Continuous Assessment, Record Keeping, and Challenges.