This paper has been conducted to determine future teachers' mathematical beliefs and to explore the relationship between their mathematical beliefs and initial teaching practice in a classroom setting, in terms of how they design the content of teaching activities, they employed the style of teaching in mathematics, and they engaged with pupils. A collective case study approach was used for this study so as to concentrate on a belief and belief in action association with numerous examples. Pre-service teachers were observed using a variety of procedures to reveal qualitative data about their teaching practice during the school-based practicum, and were then requested to complete six open-ended questions form concerning mathematical beliefs. The analysis of data revealed considerable coherence among pre-service teachers' beliefs in relation to teaching and learning of mathematics and consistent associations between their beliefs and their teaching practices in a classroom-based setting. Although pre-service teachers' accounts emphasized the use of contemporary approaches in mathematics teaching to enhance and extend students' learning of mathematics but they felt not enough confident to integrate these ideas into teaching mathematics effectively. In addition, some teachers who held a learner-based mathematical beliefs but were teaching mathematics in a classroom with traditional sense.