This study aimed at identifying specifically prospective chemistry teachers' difficulties in determining the differences between the concepts of chemical thermodynamics and kinetics. Data were collected from 67 prospective chemistry teachers at Kazim Karabekir Education Faculty of Ataturk University in Turkey during 2005-2006 academic year. Data collection performed through two different instruments. In order to determine prospective teachers' difficulties in determining the differences between the concepts of chemical thermodynamics and kinetics, a diagnostic test composed of five open-ended questions was specifically developed for this study. Thirteen participants (out of 67) were also interviewed in order to gather more information about the written responses. The analysis of results showed six major misconceptions about the difference between the concepts of chemical thermodynamics and kinetics indicating that the prospective chemistry teachers attempted to interpret the kinetics of several phenomena by using thermodynamics data. The findings reported here may contribute to understanding of undergraduates' difficulties and can be utilized in research that develops teaching strategies to overcome such difficulties. (Contains 1 table and 1 footnote.)