Problem Statement: Practice teaching is an important element in teacher education programs and it plays an active role in student teacher's obtaining and improving their teaching skills. However, student teachers have some concerns, since they are observed and evaluated by their supervisors in terms of class management, methods and techniques, preparation, and communication with students. A unique concern scale might be developed to measure the nature and degree of the concerns that affect student teachers. Purpose of the Study: The purpose of the study is to develop a unique scale that measures the types and degrees of student teachers' concerns over the course of practice teaching period. Method: A student teachers' Concern Scale was developed based on the literature and on interviews with 98 student teachers (50 males, 48 females) from different departments of Education Faculty of Gazi University in 2011-2012 academic year. The form was revised in response to peer review, and student teachers of different departments from three universities (n = 681) in Ankara (Gazi University n = 348; Hacettepe University n = 296; Ankara University n = 37) were given the revised draft of the 23-item form 423 of participants were females and 258 of them were males (Median = 22). The construct validity of the scale was examined via exploratory and confirmatory factor analyses. The reliability of the measurement was tested using Cronbach's alpha and stratified alpha methods. Findings and Results: Principle component and exploratory factor analyses showed a two-factor solution of (1) class management (11 items; variance explained: 23.16%), (2) evaluation (8 items; variance explained: 17.29%) in the first sample. Confirmatory factor analysis revealed acceptable goodness of fit indices (?[superscript 2][subscript 151] = 724.02; p = 0.00; Normed ?[superscript 2] = 4.79; CFI = 0.88; GFI = 0.94; AGFI = 0.92; RMSEA = 0.11 and 90% C.I. = 0.10 - 0.11for RMSEA), and item-total correlations were between 0.38 and 0.69. Reliability coefficients were 0.84 and 0.95 for class-management, 0.79 and 0.92 for evaluation, 0.84 for overall scale. Recommendation: Student teacher Concern Scale can be utilized to eliminate some weaknesses in practice teaching experience, improvement in programs in teacher education institutions, to guide related researchers.