This study aims to determine science students teachers' conceptions on the concepts related to "the matter and the states of the matter". 112 Turkish science student teachers participated at this research. A questionnaire consisting of thirteen open-ended items was designed to collect the data. The questionnaire aimed to reveal the students' views concerning; the features of "solid, liquid and gas" states and their application in everyday life, the state of matter at room temperature and in normal conditions, the particulate structure of matter, unique properties of each particle of matter, the relationship between the force of attraction between these particles and room temperature. The results were analyzed mainly qualitatively, but also quantitatively. As an outcome of the analysis, fourteen misconceptions were determined. These misconceptions can be categorized as "mentioning of the state of matter without specifying the temperature and the pressure", "not comprehending that liquids evaporate at any temperature", "not understanding the features of the particulate structures of solid, liquid and gas substances (volume and the number of the particles)".