Objective: The aim of this study is to develop a tool to measure the perceptions of professionals about criminals who are working with criminals or who can possibly work with them in the future. Methods: A 50-item preliminary scale was formed based on the review of the relevant literature, the pilot study and expert opinions. The scale was administered to 392 students. Results: Analysis was conducted with remaining 39 items after item-correlation analysis. The KMO value of the scale was 0.859 and the result of the Bartlett test was 1518.42. The results of the explanatory factor analysis yielded two factors and 12 items. In this scale, the first factor explained 32.42% of the total variance while the second factor explained 20% of the total variance (52.42% in total). The validity analysis of the scale was conducted on a sample of 310 students and the indices showed a good fit (χ2/sd=2.43; RMSEA=0.68; GFI=0.935; AGFI=0.905; NFI=0.902; CFI=0.94). In addition internal validity analyses were performed and the scale was found to have internal validity. In terms of the reliability analyses, Cronbach's alpha (0.82) and split-half analysis (0.80) were performed and the scales reliability was verified. Conclusion: The validity and reliability analyzes showed that the Perceptions toward Criminals Scale can be applied to professionals working with criminals or who can potentially work with them in the future [Anadolu Psikiyatri Derg 2019; 20(3.100): 41-47]