We explore the implicit representations systems as obstacles for teachers’ professional development. Their characterization requires a professional teaching epistemology model from backgrounds describing the performance of science teachers in the classroom. The research is qualitative, exploratory, interpretative and transversal, based on a case study through three instances of data collection and triangulation analysis. The Implicit Representations Systems characterized reveal various domain theories, grouped in four implicit theories: the sufficiency of meaningful learning; the difficulty of teaching and assessment that promote student self-regulation; managerial role of the teacher imposing the student a passive role, and a realistic, empirical and inductive epistemology.