In Zambia, continuous assessment (CA) is defined as an on-going, diagnostic, classroom-based process that uses a variety of assessment tools to measure learner performance (MOE, 2005:5). Over the years, examinations have been used for selection and certification, without formal considerations on school-based continuous assessment as a component in the final examinations at Grade seven level. The Ministry of Education introduced school based continuous assessment for two reasons: To improve teaching and learning and to collect school based marks to be added to the final examination marks for certification and selection. This paper deals with the implementation of school based continuous assessment, focusing on the shift from emphasising continuous testing to emphasising continuous assessment. The paper deals at length with the implementation of the CA programme, the nature of the CA Scheme and its school based assessment component, challenges in implementing the school based assessment activities, the impact of school based assessment aspects of the CA programme and the lessons learnt from the monitoring and evaluation activities. (Contains 4 figures and 1 table.)