The main purpose of this study was to examine changes in student teachers` levels of sense of efficacy before and after their student teaching practicum. Furthermore, this study examines the extent to which the variables of interest affected the student teachers` sense of efficacy before and after teaching practicum. The subjects of this study were 127 student teachers double-majoring in elementary (K through Grade 3) and early childhood education who were enrolled in student teaching credits during Fall 2009 and Spring 2010 at a Midwestern research-extensive university in the United States. Paired t-tests indicated that the student teachers who responded to both pretest and posttest reported that their sense of efficacy increased significantly over time during a student teaching experience in overall student teachers` efficacy scores. Along with the main results of this study, implications for research and practice were discussed.