The purposes of this study are; to find out the profiles of stock investors in Usak city, to determine the demographic and socio-economic factors which are affecting investors decision and to find out whether the investors behave rationally or not in their investment decisions. In order to get data for these purposes, the questionnaire is applied to stock investors. Then, obtained data were analyzed with one way anova test by using SPSS.18 statistical package program. According to results of the study; stock investors in Uşak have similar characteristics with the overall stock investors in Turkey. Investors in Uşak can’t behave rationally as they don’t have enough information on investment in stock exchange. Moreover, it is revealed that demographic and socio-economic factors such as age, gender, occupation, education level, family population and income, influenced the decisions of stock investment. It is suggested that the findings of the study may support policy makers to increase the quantity of investors and their trading volume through to take better decisions in Uşak which is not known as a major province about the issue.