Addressing all students’ needs is important for effective teaching. In teacher education programs, it is vital to introduce reform-based instructional approaches to preservice teachers (PST) while emphasizing the essence of subject matter knowledge, pedagogical content knowledge and knowledge about diverse students. This study represents preservice mathematics teachers’ perceptions about distinctively designed Mathematical Problem Solving course. The design of the course basically had an emphasis on problem solving, diversity, and equity consciousness and framed by a hypothetical learning trajectory. The data were gathered through semi-structured interviews. PSTs’ responses were analyzed by thematic analysis. PSTs’ perceptions about the Problem Solving in Mathematics course were grouped under four themes and these were efficacy, awareness, shortcomings, and problem sets as challengers. In general PSTs pointed that the course was effective on improving their previous content knowledge and belief about being a better mathematics teacher, learning heuristics in problem solving, and creating an awareness on diversity and equity while it had some shortcomings such as time management or lack of guidance needed by PSTs. Problem sets were one of the main components of the problem solving and posing structure of the course and these problems were non-routine problems which many PSTs found it difficult as well.