The aim of this study is to examine the effect of the teaching practice course on preservice elementary teachers' TISE level. In this research both qualitative and quantitative research methods were used. The participants were 43 pre-service elementary teachers from a state university in Turkey. In the quantitative part of the study, these pre-service elementary teachers filled in the TISE scale before and after the teaching practice course. Also, semi-structured interviews were carried out with 13 voluntary pre-service elementary teachers about the sources of TISE. The results indicated that the TISE level of pre-service elementary teachers was increased during the teaching practice course. The sources of pre-service elementary teachers' TISE was discussed based on the sources of self-efficacy stated by Bandura.