The present research aims to study high school teachers' experiences of continuous evaluation. Adopting a phenomenological approach and purposeful sampling, this qualitative research was carried out through semi-structured interviews with 24 high school teachers in Tabriz. The interviews were recorded and then analyzed through Smith's (1995) method. In order to increase the precision and reliability of the findings of the precise study and continuous observation at all stages of the research, the complementary comments and viewpoints of the colleagues were taken into consideration, and the participants` manuscripts were reviewed. The findings based on the experiences of the teachers about continuous evaluation were classified into 8 main themes, i.e. “the challenges in continuous assessment”, “teachers' difficulties in continuing assessment”, “mismatch between the structure and rules of the educational system and continuousassessment”, “common errors in continuous assessment” “the nature standardization in continuous assessment”, “the strengths”, “obstacles to implementation”, “disadvantages of continuous assessment” and several subthemes. The findings depict a clear picture of high school teachers` experiences of continuous evaluation.