In Bhanubhakta Higher Secondary School, we have implementation the teaching learning methodology based on continuous assessment system (CAS). The continuous assessment system (CAS) has been recognized as an integral part of everyday classroom instruction at the basic level of education. This study aims to explore the teachers’ perceptions towards continuous assessment systems at the basic level. It was designed in a qualitative model and using a semi-structured interview schedule. For Participants, six basic level school teachers were selected purposely from three selected schools in Kathmandu district. The interviews covered sociodemographic data, perceptions towards CAS, teaching styles, and personal experience using CAS, and challenges towards using CAS. An inductive analysis was used to allow for the patterns and themes to emerge. The finding of the study showed that most of the teachers were positive and only a few had negative perceptions towards the CAS along with its tools like portfolio, project work, and homework. Lack of CAS training for teachers, insufficient materials, resources, and infrastructures also seems to be a great challenge to the teachers. This study revealed the necessity to conduct CAS training to the basic level teachers and provide sufficient materials for the effective use of CAS at the basic level.